RegReplacer

A library to facilitate regex matches and replacing matches.

const regRep     = new RegReplacer(/Word/g);
const str        = "Word Word Word";
const regMatches = regRep.match(str);
console.log(regMatches.replace(["This", "is", "RegReplacer."], "matches"));
This is RegReplacer

This is RegReplacer.

Installing

npm install regreplacer

Main Example

Setup.

import RegReplacer from "../regreplacer.js";

// Generate a RegReplacer object tied to a specific regex
const regRep = new RegReplacer(/\$(\S*)/g);

// Create a string to match on
let string = "$v1 $v2 $v3";

// Calling match function on string returns a RegRepMatches object
let regMatches = regRep.match(string);

Retrieve match data.

// We can test whether any matches were found using hasMatches
let anyMatches = regMatches.hasMatches;
console.log(anyMatches); // true

// From the RegRepMatches object we can do several things
// First we can get the matches
let matches = regMatches.matches;
console.log(matches); // ['$v1', '$v2', '$v3']

// Next we can get the captures
let captures = regMatches.captures;
console.log(captures); // ['v1', 'v2', 'v3']

// Finally we can get the indices of matches
let indices = regMatches.indices;
console.log(indices); // [0, 4, 8]

Replace on matches.

// After matching, we can replace the matches with an array of values
let newString1 = regMatches.replace(["This", "is", "cool."], "matches");
console.log(newString1); // This is cool

newString2 = regMatches.replace([1, 2, 3], "matches");
console.log(newString2); // 1 2 3

Replace on captures.

// Or we can replace the captures
let newString3 = regMatches.replace(["This", "is", "cool."], "captures");
console.log(newString3); // $This $is $cool

newString4 = regMatches.replace([1, 2, 3], "captures");
console.log(newString4); // $1 $2 $3

Replacements can be done programmtically.

let capMap = {'v1':'This', 'v2':'is', 'v3':'cool'};
let reaAr = [];

for(const match of captures) {
   reaAr.push(capMap[match]);
}

let newString5 = regMatches.replace(reaAr, "matches");
console.log(newString5); // This is cool

API

RegReplacer

Main class, constructor takes a valid regex and returns a RegReplacer object. Invalid regexs will throw an error on construction.

Construction

import RegReplacer from "../regreplacer.js";

const regRep  = new RegReplacer(/\S+/g);
const regReg2 = new RegReplacer(new RegExp("/s/g"));

Returns RegReplacer object.

Methods

Match

Match function takes a word and returns a RegRepMatches Object. Will throw and error if passed anything other than a string.

const regRep  = new RegReplacer(/Word/g);
const match   = regRep.match("Word");

Returns RepRapMatches Object.

isClass

Used to determine class type equality. Implemented internally using symbols.

const regRep  = new RegReplacer(/\S+/g);
const regReg2 = new RegReplacer(new RegExp("/s/g"));
console.log(regRep.isClass(regReg2));
true

Returns boolean.

RegRepMatches

Computed Properties

hasMatches

Returns boolean value for whether or not any matches were found.

const regRep  = new RegReplacer(/W(ord)/g);
const match   = regRep.match("Word Word Word");
console.log(match.hasMatches);
true

Returns a boolean value.

matches

Returns the matches that would have been found after initializing RegReplacer and passing a string to match.

const regRep  = new RegReplacer(/Word/g);
const match   = regRep.match("Word Word Word");
console.log(match.matches);
[Word, Word, Word]

Returns empty array if no matches found.

captures

Returns the captures that would have been found after initializing RegReplacer and passing a string to match.

const regRep  = new RegReplacer(/W(ord)/g);
const match   = regRep.match("Word Word Word");
console.log(match.captures);
[ord, ord, ord]

Returns empty array if no matches/captures found.

indices

Returns the indices of the mathces that would have been found after initializing RegReplacer and passing a string to match.

const regRep  = new RegReplacer(/W(ord)/g);
const match   = regRep.match("Word Word Word");
console.log(match.indices);
[0, 5, 10]

Returns empty array if no matches found.

Methods

isClass

Used to determine class type equality. Implemented internally using symbols.

const regRep  = new RegReplacer(/Word/g);
const match   = regRep.match("Word");
const match2  = regRep.match("Word");
console.log(match.isClass(match2));
true

Returns boolean.

replace

Used to replace matches or captures with an array of values. Extra values are ignored, and insufficient values will be replaced with undefined.

// Simple replacement on matches
const regRep  = new RegReplacer(/Word/g);
const match   = regRep.match("Word Word Word");
console.log(match.replace(["This", "is", "cool"], "matches"));
"This is cool"

// Too few arguments, undefined in output
const regRep  = new RegReplacer(/Word/g);
const match   = regRep.match("Word Word Word");
console.log(match.replace([1,2], "matches"));
"1 2 undefined"

// Too many arguments, last argument ignored
const regRep  = new RegReplacer(/Word/g);
const match   = regRep.match("Word Word Word");
console.log(match.replace([1,2,3,4], "matches"));
"1 2 3"

// Add a capture group to regex and replace on captures instead
const regRep  = new RegReplacer(/W(ord)/g);
const match   = regRep.match("Word Word Word");
console.log(match.replace(["This", "is", "cool"], "captures"));
"WThis Wis Wcool"

replaceAll

Allows you to replace all matches with a single value or transform using a function.

let regRep  = new RegReplacer(/Word/g);
let match   = regRep.match("Word Word Word");
console.log(match.replaceAll("Hey", "matches"));
"Hey Hey Hey"

let regRep  = new RegReplacer(/Word/g);
let match   = regRep.match("Word Word Word");
console.log(match.replaceAll(e => e.toLowerCase() + "@@", "matches"));
"word@@ word@@ word@@"

Scripts

Testing

To run mocha/chai tests. npm run test

Examples

To run the main example. npm run ex

To run all examples. npm run exAll

License

RegReplace.js is released under the MIT license.