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A set of miscellaneous utility functions for Node.JS.
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README.md

Table of Contents

Overview

This module contains a set of miscellaneous utility functions that don't fit into any particular category.

Usage

Use npm to install the module:

npm install pixl-tools

Then use require() to load it in your code:

var Tools = require('pixl-tools');

Then call the function of your choice:

var id = Tools.generateUniqueID();

Module List

Because I use these three modules so often, I've included them in pixl-tools as a convenience. Here is how to access them:

Module Name Description
Tools.async The async module is essential for parallel and series async loops and queues.
Tools.mkdirp The mkdirp module creates directories, including parent directories.
Tools.glob The glob module performs filesystem globs (searches).
Tools.rimraf The rimraf module performs recursive directory deletes.

Example use:

var Tools = require('pixl-tools');
var async = Tools.async;
var mkdirp = Tools.mkdirp;
var glob = Tools.glob;

Function List

Here are all the functions included in the tools library, with links to full descriptions and examples:

timeNow

NUMBER timeNow( FLOOR )

This function returns the current time expressed as Epoch Seconds. Pass true if you want the value floored to the nearest integer.

var epoch = Tools.timeNow();
var floored = Tools.timeNow(true);

generateUniqueID

STRING generateUniqueID( LENGTH, SALT )

This function generates a pseudo-random alphanumeric (hexadecimal) ID by combining various bits of local entropy, and hashing it together with SHA-256. The default length is 64 characters, but you can pass in any lesser length to chop it. If you want to add your own entropy, pass it as the 2nd argument.

var id = Tools.generateUniqueID();
var id = Tools.generateUniqueID( 32 );
var id = Tools.generateUniqueID( 64, "my extra entropy!" );

Please note that this is not designed to be cryptographically secure. It doesn't use Node's crypto.randomBytes, because generating true random bits takes time, and can block execution.

generateShortID

STRING generateShortID( PREFIX )

This function generates a short, semi-unique pseudo-random alphanumeric ID using high-resolution server time, and a static counter. Both values are converted to Base-36 (lower-case alphanumeric encoding), and combined to produce a 10-12 character ID, plus an optional string prefix if provided. This algorithm allows for up to 1,296 unique IDs per millisecond, but due to server clock adjustments (NTP) this could theoretically collide with itself. Use with caution. Example:

var id = Tools.generateShortID('z');
// --> "zjcdtsls30r"

digestHex

STRING digestHex( PLAINTEXT, [ALGO] )

This function is just a simple wrapper around Node's SHA-256 or other hashing algorithms. The default is SHA-256, in which case it returns a 64-character hexadecimal hash of the given string.

var sig = Tools.digestHex( "my plaintext string" );
// --> "6b4fdfd705d05b11a56b8c3020058b666359d3939b6eda354f529ebad77695c2"

To specify the algorithm, include it as the second argument. It should be a string set to md5, sha256, etc. On recent releases of OpenSSL, typing openssl list-message-digest-algorithms will display the available digest algorithms. Example (MD5):

var sig = Tools.digestHex( "my plaintext string", "md5" );
// --> "659a30fb5d9958326b15c17e8444c123"

numKeys

INTEGER numKeys( OBJECT )

This function returns the number of keys in the specified hash.

var my_hash = { foo: "bar", baz: 12345 };
var num = Tools.numKeys( my_hash ); // 2

firstKey

STRING firstKey( OBJECT )

This function returns the first key of the hash when iterating over it. Note that hash keys are stored in an undefined order.

var my_hash = { foo: "bar", baz: 12345 };
var key = Tools.firstKey( my_hash ); // foo or baz

hashKeysToArray

ARRAY hashKeysToArray( OBJECT )

This function returns all the hash keys as an array. The values are discarded. Useful for sorting and then iterating over the sorted list.

var my_hash = { foo: "bar", baz: 12345 };
var keys = Tools.hashKeysToArray( my_hash ).sort();

for (var idx = 0, len = keys.length; idx < len; idx++) {
	var key = keys[idx];
	// do something with key and my_hash[key]
}

hashValuesToArray

ARRAY hashValuesToArray( OBJECT )

This function returns all the hash values as an array. The keys are discarded.

var my_hash = { foo: "bar", baz: 12345 };
var values = Tools.hashValuesToArray( my_hash );

for (var idx = 0, len = values.length; idx < len; idx++) {
	var value = values[idx];
	// do something with value
}

isaHash

BOOLEAN isaHash( MIXED )

This function returns true if the provided argument is a hash (object), false otherwise.

var my_hash = { foo: "bar", baz: 12345 };
var is_hash = Tools.isaHash( my_hash );

isaArray

BOOLEAN isaArray( MIXED )

This function returns true if the provided argument is an array (or is array-like), false otherwise.

var my_arr = [ "foo", "bar", 12345 ];
var is_arr = Tools.isaArray( my_arr );

copyHash

OBJECT copyHash( OBJECT, DEEP )

This function performs a shallow copy of the specified hash, and returns the copy. Pass true as the 2nd argument to perform a deep copy, which uses JSON parse/stringify.

var my_hash = { foo: "bar", baz: 12345 };
var my_copy = Tools.copyHash( my_hash );

copyHashRemoveKeys

OBJECT copyHashRemoveKeys( OBJECT, REMOVE )

This function performs a shallow copy of the specified hash, and returns the copy, but omits any keys you specify in a separate hash.

var my_hash = { foo: "bar", baz: 12345 };
var omit_these = { baz: true };
var my_copy = Tools.copyHashRemoveKeys( my_hash, omit_these );

mergeHashes

OBJECT mergeHashes( OBJECT_A, OBJECT_B )

This function merges two hashes (objects) together, and returns a new hash which contains the combination of the two keys (shallow copy). The 2nd hash takes precedence over the first, in the event of duplicate keys.

var hash1 = { foo: "bar" };
var hash2 = { baz: 12345 };
var combo = Tools.mergeHashes( hash1, hash2 );

mergeHashInto

VOID mergeHashInto( OBJECT_A, OBJECT_B )

This function shallow-merges {OBJECT_B} into {OBJECT_A}. There is no return value. Existing keys are replaced in {OBJECT_A}.

var hash1 = { foo: "bar" };
var hash2 = { baz: 12345 };
Tools.mergeHashInto( hash1, hash2 );

parseQueryString

OBJECT parseQueryString( URL )

This function parses a standard URL query string, and returns a hash with key/value pairs for every query parameter. Duplicate params are clobbered, the latter prevails. Values are URL-unescaped, and all of them are strings. The function accepts a full URL, or just the query string portion.

var url = 'http://something.com/hello.html?foo=bar&baz=12345';
var query = Tools.parseQueryString( url );
var foo = query.foo; // "bar"
var baz = query.baz; // "12345"

Please note that this is a very simple function, and you should probably use the built-in Node.js querystring module instead.

composeQueryString

STRING composeQueryString( OBJECT )

This function takes a hash of key/value pairs, and constructs a URL query string out of it. Values are URL-escaped.

var my_hash = { foo: "bar", baz: 12345 };
var qs = Tools.composeQueryString( my_hash );
// --> "?foo=bar&baz=12345"

Please note that this is a very simple function, and you should probably use the built-in Node.js querystring module instead.

findObjectsIdx

ARRAY findObjectsIdx( ARRAY, CRITERIA )

This function iterates over an array of hashes, and returns all the array indexes whose objects have keys which match a given criteria hash.

var list = [
	{ id: 12345, name: "Joe", eyes: "blue" },
	{ id: 12346, name: "Frank", eyes: "brown" },
	{ id: 12347, name: "Cynthia", eyes: "blue" }
];
var criteria = { eyes: "blue" };

var idxs = Tools.findObjectsIdx( list, criteria );
// --> [0, 2]

findObjectIdx

INTEGER findObjectIdx( ARRAY, CRITERIA )

This function iterates over an array of hashes, and returns the first array index whose object has keys which match a given criteria hash. If no objects match, -1 is returned.

var list = [
	{ id: 12345, name: "Joe", eyes: "blue" },
	{ id: 12346, name: "Frank", eyes: "brown" },
	{ id: 12347, name: "Cynthia", eyes: "blue" }
];
var criteria = { eyes: "blue" };

var idx = Tools.findObjectIdx( list, criteria );
// --> 0

findObject

OBJECT findObject( ARRAY, CRITERIA )

This function iterates over an array of hashes, and returns the first item whose object has keys which match a given criteria hash. If no objects match, null is returned.

var list = [
	{ id: 12345, name: "Joe", eyes: "blue" },
	{ id: 12346, name: "Frank", eyes: "brown" },
	{ id: 12347, name: "Cynthia", eyes: "blue" }
];
var criteria = { eyes: "blue" };

var obj = Tools.findObject( list, criteria );
// --> { id: 12345, name: "Joe", eyes: "blue" }

findObjects

ARRAY findObjects( ARRAY, CRITERIA )

This function iterates over an array of hashes, and returns all the items whose objects have keys which match a given criteria hash.

var list = [
	{ id: 12345, name: "Joe", eyes: "blue" },
	{ id: 12346, name: "Frank", eyes: "brown" },
	{ id: 12347, name: "Cynthia", eyes: "blue" }
];
var criteria = { eyes: "blue" };

var objs = Tools.findObjects( list, criteria );
// --> [{ id: 12345, name: "Joe", eyes: "blue" }, { id: 12347, name: "Cynthia", eyes: "blue" }]

deleteObject

BOOLEAN deleteObject( ARRAY, CRITERIA )

This function iterates over an array of hashes, and deletes the first item whose object has keys which match a given criteria hash. It returns true for success or false if no matching object could be found.

var list = [
	{ id: 12345, name: "Joe", eyes: "blue" },
	{ id: 12346, name: "Frank", eyes: "brown" },
	{ id: 12347, name: "Cynthia", eyes: "blue" }
];
var criteria = { eyes: "blue" };

Tools.deleteObject( list, criteria );
// list will now contain only Frank and Cynthia

deleteObjects

INTEGER deleteObjects( ARRAY, CRITERIA )

This function iterates over an array of hashes, and deletes all items whose objects have keys which match a given criteria hash. It returns the number of objects deleted.

var list = [
	{ id: 12345, name: "Joe", eyes: "blue" },
	{ id: 12346, name: "Frank", eyes: "brown" },
	{ id: 12347, name: "Cynthia", eyes: "blue" }
];
var criteria = { eyes: "blue" };

Tools.deleteObjects( list, criteria );
// list will now contain only Frank

alwaysArray

ARRAY alwaysArray( MIXED )

This function will wrap anything passed to it into an array and return the array, unless the item passed is already an array, in which case it is simply returned verbatim.

var arr = Tools.alwaysArray( maybe_array );

sub

STRING sub( TEMPLATE, ARGS, FATAL )

This function performs placeholder substitution on a string, using square bracket delimited placeholders which may contain simple keys or even paths.

var tree = {
	folder1: {
		file1: "foo",
		folder2: {
			file2: "bar"
		}
	}
};
var template = "Hello, I would like [/folder1/folder2/file2] and also [/folder1/file1] please!";

var str = Tools.sub( template, tree );
// --> "Hello, I would like bar and also foo please!"

You can omit the leading slashes if you are doing single-level hash lookups.

If you pass true for the FATAL argument, the function will return null if any variable lookups fail. The default behavior is to preserve the original formatting (with placeholders and all) if the lookup fails.

setPath

BOOLEAN setPath( OBJECT, PATH, VALUE )

This function will set a property value inside a hash/array tree, by first traversing a directory-style path. Will auto-create new objects if needed. You can use either dir/slash/syntax or dot.path.syntax. Returns true on success or false on failure.

var tree = {
	folder1: {
		file1: "foo"
	}
};

Tools.setPath( tree, "folder1/folder2/file2", "bar" );

For walking through arrays, simply provide the index number of the element you want.

getPath

MIXED getPath( OBJECT, PATH )

This function will perform a directory-style path lookup on a hash/array tree, returning whatever object or value is pointed to, or undefined if not found. You can use either dir/slash/syntax or dot.path.syntax.

var tree = {
	folder1: {
		file1: "foo",
		folder2: {
			file2: "bar"
		}
	}
};

var file = Tools.getPath( tree, "folder1/folder2/file2" );
// --> "bar"

var file = Tools.getPath( tree, "folder1.folder2.file2" );
// --> "bar"

For walking into arrays, simply provide the index number of the element you want.

getDateArgs

OBJECT getDateArgs( MIXED )

This function parses any date string, Epoch timestamp or Date object, and produces a hash with the following keys (all localized to the current timezone):

Key Sample Value Description
year 2015 Full year as integer.
yy "15" 2-digit year as string, with padded zeros if needed.
yyyy "2015" 4-digit year as string.
mon 3 Month of year as integer (1 - 12).
mm "03" 2-digit month as string with padded zeros if needed.
mmm "Mar" Month name abbreviated to first three letters.
mmmm "March" Full month name.
mday 6 Day of month as integer (1 - 31).
dd "06" 2-digit day as string with padded zeros if needed.
wday 4 Day of week as integer (0 - 6), starting with Sunday.
ddd "Thu" Weekday name abbreviated to first three letters.
dddd "Thursday" Full weekday name.
hour 9 Hour of day as integer (0 - 23).
hour12 9 Hour expressed in 12-hour time (i.e. 3 PM = 3).
hh "09" 2-digit hour as string with padded zeros if needed.
min 2 Minute of hour as integer (0 - 59).
mi "02" 2-digit minute as string with padded zeros if needed.
sec 10 Second of minute as integer (0 - 59).
ss "10" 2-digit second as string with padded zeros if needed.
msec 999 Millisecond of second as integer (0 - 999).
ampm "am" String representing ante meridiem (am) or post meridiem (pm).
AMPM "AM" Upper-case version of ampm.
yyyy_mm_dd "2015/03/06" Formatted string representing date in YYYY/MM/DD format.
hh_mi_ss "09:02:10" Formatted string representing local time in HH:MI:SS format.
epoch 1425661330 Epoch seconds used to generate all the date properties.
offset -8 Local offset from GMT/UTC in hours.
tz "GMT-8" Formatted GMT hour offset string.

Example usage:

var args = Tools.getDateArgs( new Date() );
var date_str = args.yyyy + '/' + args.mm + '/' + args.dd;

getTimeFromArgs

INTEGER getTimeFromArgs( OBJECT )

This function will recalculate a date given an args object as returned from getDateArgs(). It allows you to manipulate the year, mon, mday, hour, min and/or sec properties, and will return the computed Epoch seconds from the new set of values. Example:

var args = Tools.getDateArgs( new Date() );
args.mday = 15;

var epoch = Tools.getTimeFromArgs(args);

This example would return the Epoch seconds from the 15th day of the current month, in the current year, and using the current time of day.

normalizeTime

INTEGER normalizeTime( INTEGER, OBJECT )

This function will "normalize" (i.e. quantize) an Epoch value to the nearest minute, hour, day, month, or year. Meaning, you can pass in an Epoch time value, and have it return a value of the start of the current hour, midnight on the current day, the 1st of the month, etc. To do this, pass in an object containing any keys you wish to change, e.g. year, mon, mday, hour, min and/or sec. Example:

var midnight = Tools.normalizeTime( Tools.timeNow(), { hour: 0, min: 0, sec: 0 } );

You can actually set the values to non-zero. For example, to return the Epoch time of exactly noon today:

var noon = Tools.normalizeTime( Tools.timeNow(), { hour: 12, min: 0, sec: 0 } );

formatDate

STRING formatDate( MIXED, STRING )

This function parses any date string, Epoch timestamp or Date object, and produces a formatted date/time string according to a custom template, and in the local timezone. The template is populated using sub() (i.e. square bracket syntax) and can use any of the date/time properties returned by getDateArgs(). Examples:

var now = new Date();

var str = Tools.formatDate( now, "[yyyy]/[mm]/[dd]" );
// 2019/03/22

var str = Tools.formatDate( now, "[dddd], [mmmm] [mday], [yyyy]" );
// Friday, March 22, 2019

var str = Tools.formatDate( now, "[hour12]:[mi] [ampm]" );
// 10:43 am

getTextFromBytes

STRING getTextFromBytes( BYTES, PRECISION )

This function generates a human-friendly text string given a number of bytes. It reduces the units to K, MB, GB or TB as needed, and allows a configurable amount of precision after the decimal point. The default is one decimal of precision (specify as 1, 10, 100, etc.).

var str = Tools.getTextFromBytes( 0 );    // "0 bytes"
var str = Tools.getTextFromBytes( 1023 ); // "1023 bytes"
var str = Tools.getTextFromBytes( 1024 ); // "1 K"
var str = Tools.getTextFromBytes( 1126 ); // "1.1 K"

var str = Tools.getTextFromBytes( 1599078, 1 ); // "1 MB"
var str = Tools.getTextFromBytes( 1599078, 10 ); // "1.5 MB"
var str = Tools.getTextFromBytes( 1599078, 100 ); // "1.52 MB"
var str = Tools.getTextFromBytes( 1599078, 1000 ); // "1.525 MB"

getBytesFromText

INTEGER getBytesFromText( STRING )

This function parses a string containing a human-friendly size count (e.g. 45 bytes or 1.5 MB) and converts it to raw bytes.

var bytes = Tools.getBytesFromText( "0 bytes" ); // 0
var bytes = Tools.getBytesFromText( "1023 bytes" ); // 1023
var bytes = Tools.getBytesFromText( "1 K" ); // 1024
var bytes = Tools.getBytesFromText( "1.1k" ); // 1126
var bytes = Tools.getBytesFromText( "1.525 MB" ); // 1599078	

commify

STRING commify( INTEGER )

This function adds commas to long numbers following US-style formatting rules (add comma every 3 digits counting from right side). Only positive integers are supported.

var c = Tools.commify( 123 ); // "123"
var c = Tools.commify( 1234 ); // "1,234"
var c = Tools.commify( 1234567890 ); // "1,234,567,890"

shortFloat

NUMBER shortFloat( NUMBER, [PLACES] )

This function "shortens" a floating point number by only allowing up to N digits after the decimal point (defaults to 2). You can customize this by passing an optional 2nd argument. Examples:

var num1 = Tools.shortFloat( 0.12345 ); // 0.12
var num2 = Tools.shortFloat( 0.00001 ); // 0.0
var num3 = Tools.shortFloat( 0.00123, 3 ); // 0.001

pct

STRING pct( AMOUNT, MAX, FLOOR )

This function calculates a percentage given an arbitrary numerical amount and a maximum value, and returns a formatted string with a '%' symbol. Pass true as the 3rd argument to floor the percentage to the nearest integer. Otherwise the value is shortened with shortFloat().

var p = Tools.pct( 5, 10 ); // "50%"
var p = Tools.pct( 0, 1 );  // "0%"
var p = Tools.pct( 751, 1000 ); // "75.1%"
var p = Tools.pct( 751, 1000, true ); // "75%"

zeroPad

STRING zeroPad( NUMBER, MAX )

This function adds zeros to the left side of a number, until the total string length meets a specified maximum (up to 10 characters). The return value is a string, not a number.

var padded = Tools.zeroPad( 5, 1 ); // "5"
var padded = Tools.zeroPad( 5, 2 ); // "05"
var padded = Tools.zeroPad( 5, 3 ); // "005"
var padded = Tools.zeroPad( 100, 3 ); // "100"
var padded = Tools.zeroPad( 100, 4 ); // "0100"
var padded = Tools.zeroPad( 100, 5 ); // "00100"

clamp

NUMBER clamp( NUMBER, MIN, MAX )

This function performs a simple mathematical "clamp" operation, restricting a value between a defined range. This is just a convenience method, which can save you a few keystrokes. Example:

var clamped = Tools.clamp( 50, 0, 10 );
// --> 10

lerp

NUMBER lerp( START, END, AMOUNT )

This function performs linear interpolation between two values and a specified amount between 0.0 and 1.0. This is just a convenience method, which can save you a few keystrokes. Example:

var lerped = Tools.lerp( 0, 50, 0.25 );
// --> 12.5

getTextFromSeconds

STRING getTextFromSeconds( NUMBER, ABBREVIATE, SHORTEN )

This function generates a human-friendly time string given a number of seconds. It reduces the units to minutes, hours or days as needed. You can also abbreviate the output, and shorten the extra precision.

var str = Tools.getTextFromSeconds( 0 ); // "0 seconds"
var str = Tools.getTextFromSeconds( 86400 ); // "1 day"
var str = Tools.getTextFromSeconds( 90 ); // "1 minute, 30 seconds"
var str = Tools.getTextFromSeconds( 90, true ); // "1 min, 30 sec"
var str = Tools.getTextFromSeconds( 90, false, true ); // "1 minute"
var str = Tools.getTextFromSeconds( 90, true, true ); // "1 min"

getSecondsFromText

INTEGER getSecondsFromText( STRING )

This function parses a string containing a human-friendly time (e.g. 45 minutes or 7 days) and converts it to raw seconds. It accepts seconds, minutes, hours, days and/or weeks. It does not interpret "months" or "years" because those are non-exact measurements.

var sec = Tools.getSecondsFromText( "1 second" ); // 1
var sec = Tools.getSecondsFromText( "2min" ); // 120
var sec = Tools.getSecondsFromText( "30m" ); // 1800
var sec = Tools.getSecondsFromText( "12 HOURS" ); // 43200
var sec = Tools.getSecondsFromText( "1day" ); // 86400

getNiceRemainingTime

STRING getNiceRemainingTime( ELAPSED, COUNTER, MAX, ABBREV, SHORTEN )

This function calculates the estimated remaining time on a job in progress, given the elapsed time in seconds, an arbitrary counter representing the job's progress, and a maximum value for the counter.

var remain = Tools.getNiceRemainingTime( 45, 0.75, 1.0 );
// --> "15 seconds"

var remain = Tools.getNiceRemainingTime( 3640, 0.75, 1.0 );
// --> "20 minutes, 13 seconds"

var remain = Tools.getNiceRemainingTime( 3640, 0.75, 1.0, true );
// --> "20 min, 13 sec"

var remain = Tools.getNiceRemainingTime( 3640, 0.75, 1.0, false, true );
// --> "20 minutes"

var remain = Tools.getNiceRemainingTime( 3640, 0.75, 1.0, true, true );
// --> "20 min"

Note that this works best when the job's progress is somewhat constant. If it proceeds at a varying pace, the remaining time may appear to go too fast or too slow at times. It always computes the average speed over the course of the time elapsed, versus the current progress.

randArray

MIXED randArray( ARRAY )

This function picks a random element from the given array, and returns it.

var fruit = ['apple', 'orange', 'banana'];
var rand = Tools.randArray( fruit );

pluralize

STRING pluralize( STRING, NUMBER )

This function pluralizes a string using US-English rules, given an arbitrary number. This is useful when constructing human-friendly sentences containing a quantity of things, and you wish to say either "thing" or "things" depending on the number.

var list = ['apple', 'orange', 'banana'];
var text = "You have " + list.length + Tools.pluralize(" item", list.length) + " in your list.";
// --> "You have 3 items in your list.";

escapeRegExp

STRING escapeRegExp( STRING )

This function escapes a string so that it can be used inside a regular expression. Meaning, any regular expression metacharacters are prefixed with a backslash, so they are interpreted literally. It was taken from the MDN Regular Expression Guide.

ucfirst

STRING ucfirst( STRING )

The function upper-cases the first character of a string, and lower-cases the rest. This is very similar to the Perl core function of the same name. Example:

var first_name = Tools.ucfirst( 'george' );
// --> "George"

getErrorDescription

STRING getErrorDescription( ERROR )

This function takes a standard Node.js System Error object, such as one emitted when a filesystem or network error occurs, and produces a prettier and more verbose string description. It uses the 3rd party errno package, and adds its own decorations as well. Example:

require('fs').readFile( '/bad/file.txt', function(err, data) {
	if (err) {
		console.log( "Native Error: " + err.message );
		console.log( "Better Error: " + Tools.getErrorDescription(err) );
	}
} );

// Outputs:
// Native Error: ENOENT, open '/bad/file.txt'
// Better Error: No such file or directory (ENOENT, open '/bad/file.txt')

Basically it resolves the Node.js error codes such as ENOENT to a human-readable string (i.e. No such file or directory), but also appends the raw native error message in parenthesis as well.

bufferSplit

ARRAY bufferSplit( BUFFER, SEPARATOR )

This function splits a buffer into an array of chunks, given a separator (string or buffer). It works similarly to the String.split core function, with two main differences. First, the separator cannot be a regular expression (it must be a string or another buffer), and second, the returned split buffer chunks will occupy the same memory space as the original buffer. Example:

var EOL = require('os').EOL;
var data = require('fs').readFileSync( 'some_file.csv' );
var lines = Tools.bufferSplit( data, EOL );

fileEachLine

VOID fileEachLine( FILE, OPTS, ITERATOR, CALLBACK )

This function iterates over a file line by line, firing ITERATOR for each. This is done in asynchronous fashion, akin to the async module. Your ITERATOR function is passed the line (encoded string or buffer) and a callback to fire. When all the lines are completed, the main CALLBACK is fired once, including an error or not. This is designed to handle huge files without using much memory at all.

The OPTS object may include:

Property Name Default Value Description
buffer_size 1024 How many bytes to read from the file at a time.
eol os.EOL The end-of-line separator, defaults to the current system EOL.
encoding utf8 The encoding to use for each line, set to null if you want buffers.

Example:

Tools.fileEachLine( "my_large_spreadsheet.csv",
	function(line, callback) {
		// this is fired for each line
		var columns = line.split(/\,\s*/);
		// do something with the data here, possibly async
		// fire callback for next line, pass error to abort
		callback();
	},
	function(err) {
		// all lines are complete
		if (err) throw err;
	}
);

getpwnam

OBJECT getpwnam( USERNAME, [USE_CACHE] )

This function fetches local user account information, give a username or numerical UID. This is similar to the POSIX getpwnam function, which is missing from Node core. This function works on Linux and OS X only. It runs in synchronous mode, and returns an object with the following properties, or null on error:

Property Name Sample Value Description
username jhuckaby The username of the account.
password **** The hashed password of the account (often masked).
uid 501 The numerical UID (User ID) of the account.
gid 501 The numeric GID (Group ID) of the account.
name Joseph Huckaby The full name of the user.
dir /home/jhuckaby The home directory path of the user.
shell /bin/bash The login shell used by the user.

If you pass true as the 2nd argument, the user information will be cached in RAM for future queries on the same username or UID. Example use:

var info = Tools.getpwnam( "jhuckaby", true );
if (info) {
	process.chdir( info.dir );
}

tween

NUMBER tween( START, END, AMOUNT, MODE, ALGORITHM )

This function calculates a tween between two numbers, and returns the in-between value. For example, this can be used to control animation with "easing" (i.e. ease-in, ease-out), and also custom mathematical curves like quadratic, quintic, etc. Example use:

var x = Tools.tween( 0, 150, 0.5, 'EaseOut', 'Quadratic' );

The output will be somewhere between 0 and 150, controlled by the EaseOut mode and Quadratic algorithm. If you had selected the Linear algorithm, this would be exactly 75 (halfway between the start and end).

Here is a more detailed list of the function arguments:

Argument Description
START The starting value for the property (any number).
END The ending value for the property (any number).
AMOUNT This value should be between 0.0 and 1.0, and sets the position along the animation path.
MODE The animation mode as string, one of EaseIn, EaseOut or EaseInOut.
ALGORITHM The algorithm name as string, one of Linear, Quadratic, Cubic, Quartetic, Quintic, Sine or Circular.

License

The MIT License

Copyright (c) 2015 - 2019 Joseph Huckaby.

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

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