string-collapse-leading-whitespace

string-collapse-leading-whitespace

Collapse the leading and trailing whitespace of a string

Table of Contents

• Install
• Idea
• API - Input
• API - Output
• Example
• Purpose
• Contributing
• Licence

Install

npm i string-collapse-leading-whitespace

The default is exported, so instead of "collapseLeadingWhitespace" below, you can name the consumed function however you want.

Consume via a require():

const collapseLeadingWhitespace = require("string-collapse-leading-whitespace");

or as an ES Module:

import collapseLeadingWhitespace from "string-collapse-leading-whitespace";

or for web pages, as a production-ready minified script file (so-called "UMD build"), straight from CDN:

<script src="https://cdn.jsdelivr.net/npm/string-collapse-leading-whitespace/dist/string-collapse-leading-whitespace.umd.js"></script>

// in which case you get a global variable "stringCollapseLeadingWhitespace" which you consume like this:
const collapseLeadingWhitespace = stringCollapseLeadingWhitespace;

This package has three builds in dist/ folder:

Type	Key in package.json	Path	Size
Main export - CommonJS version, transpiled to ES5, contains require and module.exports	main	dist/string-collapse-leading-whitespace.cjs.js	2 KB
ES module build that Webpack/Rollup understands. Untranspiled ES6 code with import/export.	module	dist/string-collapse-leading-whitespace.esm.js	2 KB
UMD build for browsers, transpiled, minified, containing iife's and has all dependencies baked-in	browser	dist/string-collapse-leading-whitespace.umd.js	1018 B

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Idea

// does nothing to trimmed strings:
'aaa' => 'aaa'
// if leading or trailing whitespace doesn't contain \n, collapse to a single space
'  aaa   ' => ' aaa '
// otherwise, collapse to a single \n
'     \n\n   aaa  \n\n\n    ' => '\naaa\n'

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API - Input

Input argument	Type	Obligatory?	Default	Description
str	String	yes	undefined	Source string to work on
originalLimitLinebreaksCount	Natural number (excl. zero)	no	1	Maximum line breaks that will be put when leading or trailing whitespace contains any.

If first input argument is not a string, it will be just returned back, untouched. If second input argument is zero or falsey or not a number, it will be set to 1 and application will continue as normal.

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API - Output

String of zero or more characters. If input was not a string, same thing will be returned back, without an error.

Example

const collapseLeadingWhitespace = require("string-collapse-leading-whitespace");
const someStr = "\n\n\n tralalaa \n\n";
const res1 = collapseLeadingWhitespace(someStr); // default is one leading/trailing line break
console.log(
  `${`\u001b[${33}m${`res1`}\u001b[${39}m`} = ${JSON.stringify(res1, null, 4)}`
);
// res1 = "\ntralalaa\n"
// result has single leading/trailing linebreak because second argument's default is 1.

// -----------------------------------------------------------------------------

// now, same thing, but set it to two:
const res2 = collapseLeadingWhitespace(someStr, 2); // notice second arg set
console.log(
  `${`\u001b[${33}m${`res2`}\u001b[${39}m`} = ${JSON.stringify(res2, null, 4)}`
);
// res2 = "\n\ntralalaa\n\n"
// result has two leading, two trailing. Leading count was capped, trailing reached max anyway. There were two only leading line breaks.
// Notice spaces/tabs are/would be removed.

// -----------------------------------------------------------------------------

// now set it to three:
const res3 = collapseLeadingWhitespace(someStr, 3); // notice second arg set
console.log(
  `${`\u001b[${33}m${`res3`}\u001b[${39}m`} = ${JSON.stringify(res3, null, 4)}`
);
// res3 = "\n\n\ntralalaa\n\n"
// result has three leading line breaks, them maxed out - there were three. There were two trailing linebreaks, allowance was for three. End result - two trailing linebreaks.
// All spaces were removed.

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Purpose

I'm going to use it in ranges-push.

Contributing

• If you see an error, raise an issue.
• If you want a new feature but can't code it up yourself, also raise an issue. Let's discuss it.
• If you tried to use this package, but something didn't work out, also raise an issue. We'll try to help.
• If you want to contribute some code, fork the monorepo via GitLab, then write code, then file a pull request on GitLab. We'll merge it in and release.

In monorepo, npm libraries are located in packages/ folder. Inside, the source code is located either in src/ folder (normal npm library) or in the root, cli.js (if it's a command-line application).

The npm script "dev", the "dev": "rollup -c --dev --silent" builds the development version retaining all console.logs with row numbers. It's handy to have js-row-num-cli installed globally so you can automatically update the row numbers on all console.logs.

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Licence

MIT License

Copyright (c) 2015-2019 Roy Revelt and other contributors