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util: add Map and Set inspection support
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PR-URL: #1471
Reviewed-By: Chris Dickinson <christopher.s.dickinson@gmail.com>
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monsanto authored and chrisdickinson committed Apr 26, 2015
1 parent 5178f93 commit bf7ac08
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Showing 2 changed files with 172 additions and 13 deletions.
120 changes: 107 additions & 13 deletions lib/util.js
Original file line number Diff line number Diff line change
@@ -1,6 +1,7 @@
'use strict';

const uv = process.binding('uv');
const Debug = require('vm').runInDebugContext('Debug');

const formatRegExp = /%[sdj%]/g;
exports.format = function(f) {
Expand Down Expand Up @@ -192,6 +193,14 @@ function arrayToHash(array) {
}


function inspectPromise(p) {
var mirror = Debug.MakeMirror(p, true);
if (!mirror.isPromise())
return null;
return {status: mirror.status(), value: mirror.promiseValue().value_};
}


function formatValue(ctx, value, recurseTimes) {
// Provide a hook for user-specified inspect functions.
// Check that value is an object with an inspect function on it
Expand Down Expand Up @@ -276,14 +285,43 @@ function formatValue(ctx, value, recurseTimes) {
}
}

var base = '', array = false, braces = ['{', '}'];
var base = '', empty = false, braces, formatter;

// Make Array say that they are Array
if (Array.isArray(value)) {
array = true;
braces = ['[', ']'];
empty = value.length === 0;
formatter = formatArray;
} else if (value instanceof Set) {
braces = ['Set {', '}'];
// With `showHidden`, `length` will display as a hidden property for
// arrays. For consistency's sake, do the same for `size`, even though this
// property isn't selected by Object.getOwnPropertyNames().
if (ctx.showHidden)
keys.unshift('size');
empty = value.size === 0;
formatter = formatSet;
} else if (value instanceof Map) {
braces = ['Map {', '}'];
// Ditto.
if (ctx.showHidden)
keys.unshift('size');
empty = value.size === 0;
formatter = formatMap;
} else {
// Only create a mirror if the object superficially looks like a Promise.
var promiseInternals = value instanceof Promise && inspectPromise(value);
if (promiseInternals) {
braces = ['Promise {', '}'];
formatter = formatPromise;
} else {
braces = ['{', '}'];
empty = true; // No other data than keys.
formatter = formatObject;
}
}

empty = empty === true && keys.length === 0;

// Make functions say that they are functions
if (typeof value === 'function') {
var n = value.name ? ': ' + value.name : '';
Expand Down Expand Up @@ -323,7 +361,7 @@ function formatValue(ctx, value, recurseTimes) {
base = ' ' + '[Boolean: ' + formatted + ']';
}

if (keys.length === 0 && (!array || value.length === 0)) {
if (empty === true) {
return braces[0] + base + braces[1];
}

Expand All @@ -337,14 +375,7 @@ function formatValue(ctx, value, recurseTimes) {

ctx.seen.push(value);

var output;
if (array) {
output = formatArray(ctx, value, recurseTimes, visibleKeys, keys);
} else {
output = keys.map(function(key) {
return formatProperty(ctx, value, recurseTimes, visibleKeys, key, array);
});
}
var output = formatter(ctx, value, recurseTimes, visibleKeys, keys);

ctx.seen.pop();

Expand Down Expand Up @@ -397,6 +428,13 @@ function formatError(value) {
}


function formatObject(ctx, value, recurseTimes, visibleKeys, keys) {
return keys.map(function(key) {
return formatProperty(ctx, value, recurseTimes, visibleKeys, key, false);
});
}


function formatArray(ctx, value, recurseTimes, visibleKeys, keys) {
var output = [];
for (var i = 0, l = value.length; i < l; ++i) {
Expand All @@ -417,6 +455,59 @@ function formatArray(ctx, value, recurseTimes, visibleKeys, keys) {
}


function formatSet(ctx, value, recurseTimes, visibleKeys, keys) {
var output = [];
value.forEach(function(v) {
var nextRecurseTimes = recurseTimes === null ? null : recurseTimes - 1;
var str = formatValue(ctx, v, nextRecurseTimes);
output.push(str);
});
keys.forEach(function(key) {
output.push(formatProperty(ctx, value, recurseTimes, visibleKeys,
key, false));
});
return output;
}


function formatMap(ctx, value, recurseTimes, visibleKeys, keys) {
var output = [];
value.forEach(function(v, k) {
var nextRecurseTimes = recurseTimes === null ? null : recurseTimes - 1;
var str = formatValue(ctx, k, nextRecurseTimes);
str += ' => ';
str += formatValue(ctx, v, nextRecurseTimes);
output.push(str);
});
keys.forEach(function(key) {
output.push(formatProperty(ctx, value, recurseTimes, visibleKeys,
key, false));
});
return output;
}

function formatPromise(ctx, value, recurseTimes, visibleKeys, keys) {
var output = [];
var internals = inspectPromise(value);
if (internals.status === 'pending') {
output.push('<pending>');
} else {
var nextRecurseTimes = recurseTimes === null ? null : recurseTimes - 1;
var str = formatValue(ctx, internals.value, nextRecurseTimes);
if (internals.status === 'rejected') {
output.push('<rejected> ' + str);
} else {
output.push(str);
}
}
keys.forEach(function(key) {
output.push(formatProperty(ctx, value, recurseTimes, visibleKeys,
key, false));
});
return output;
}


function formatProperty(ctx, value, recurseTimes, visibleKeys, key, array) {
var name, str, desc;
desc = Object.getOwnPropertyDescriptor(value, key) || { value: value[key] };
Expand Down Expand Up @@ -488,7 +579,10 @@ function reduceToSingleString(output, base, braces) {

if (length > 60) {
return braces[0] +
(base === '' ? '' : base + '\n ') +
// If the opening "brace" is too large, like in the case of "Set {",
// we need to force the first item to be on the next line or the
// items will not line up correctly.
(base === '' && braces[0].length === 1 ? '' : base + '\n ') +
' ' +
output.join(',\n ') +
' ' +
Expand Down
65 changes: 65 additions & 0 deletions test/parallel/test-util-inspect.js
Original file line number Diff line number Diff line change
Expand Up @@ -235,3 +235,68 @@ if (typeof Symbol !== 'undefined') {
assert.equal(util.inspect(subject, options), '[ 1, 2, 3, [length]: 3, [Symbol(symbol)]: 42 ]');

}

// test Set
assert.equal(util.inspect(new Set), 'Set {}');
assert.equal(util.inspect(new Set([1, 2, 3])), 'Set { 1, 2, 3 }');
var set = new Set(['foo']);
set.bar = 42;
assert.equal(util.inspect(set, true), 'Set { \'foo\', [size]: 1, bar: 42 }');

// test Map
assert.equal(util.inspect(new Map), 'Map {}');
assert.equal(util.inspect(new Map([[1, 'a'], [2, 'b'], [3, 'c']])),
'Map { 1 => \'a\', 2 => \'b\', 3 => \'c\' }');
var map = new Map([['foo', null]]);
map.bar = 42;
assert.equal(util.inspect(map, true),
'Map { \'foo\' => null, [size]: 1, bar: 42 }');

// test Promise
assert.equal(util.inspect(Promise.resolve(3)), 'Promise { 3 }');
assert.equal(util.inspect(Promise.reject(3)), 'Promise { <rejected> 3 }');
assert.equal(util.inspect(new Promise(function() {})), 'Promise { <pending> }');
var promise = Promise.resolve('foo');
promise.bar = 42;
assert.equal(util.inspect(promise), 'Promise { \'foo\', bar: 42 }');

// Make sure it doesn't choke on polyfills. Unlike Set/Map, there is no standard
// interface to synchronously inspect a Promise, so our techniques only work on
// a bonafide native Promise.
var oldPromise = Promise;
global.Promise = function() { this.bar = 42; };
assert.equal(util.inspect(new Promise), '{ bar: 42 }');
global.Promise = oldPromise;


// Test alignment of items in container
// Assumes that the first numeric character is the start of an item.

function checkAlignment(container) {
var lines = util.inspect(container).split('\n');
var pos;
lines.forEach(function(line) {
var npos = line.search(/\d/);
if (npos !== -1) {
if (pos !== undefined)
assert.equal(pos, npos, 'container items not aligned');
pos = npos;
}
});
}

var big_array = [];
for (var i = 0; i < 100; i++) {
big_array.push(i);
}

checkAlignment(big_array);
checkAlignment(function() {
var obj = {};
big_array.forEach(function(v) {
obj[v] = null;
});
return obj;
}());
checkAlignment(new Set(big_array));
checkAlignment(new Map(big_array.map(function (y) { return [y, null] })));

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