README.md

@asset-pipe/common

Common utility methods shared accross the asset-pipe project. Intended for use by other modules in the asset-pipe project

Installation

$ npm install @asset-pipe/common

API

This module have the following API:

IdHasher()

Writable stream to build a hash out of all the id properties in an asset feed.

const common = require('@asset-pipe/common');
const JSONStream = require('JSONStream');
const fs = require('fs');

const file = fs.createReadStream('./asset-feed.json');
const parser = JSONStream.parse('*');
const hasher = new common.IdHasher();

file.pipe(parser).pipe(hasher);

hasher.on('finish', () => {
    console.log(hasher.hash);
});

SourceHasher()

Writable stream to build a hash out of all the source properties in an asset feed.

const common = require('@asset-pipe/common');
const JSONStream = require('JSONStream');
const fs = require('fs');

const file = fs.createReadStream('./asset-feed.json');
const parser = JSONStream.parse('*');
const hasher = new common.SourceHasher();

file.pipe(parser).pipe(hasher);

hasher.on('finish', () => {
    console.log(hasher.hash);
});

FileHasher()

Writable stream to build a hash out of the content of a non object mode stream.

const common = require('@asset-pipe/common');
const fs = require('fs');

const file = fs.createReadStream('./assets.js');
const hasher = new common.FileHasher();

file.pipe(hasher);

hasher.on('finish', () => {
    console.log(hasher.hash);
});

hasher(source)

Creates a hash out of a String or Buffer

Arguments:

• source - String or Buffer - the contents to hash

Returns a hash.

const common = require('@asset-pipe/common');
const fs = require('fs');

fs.readFile('.assets.js', (err, data) => {
    const hash = common.hasher(data);
    console.log(hash);
});

createTemporaryFilename(fileType)

Creates a random file name intended to be used for temp files.

Arguments:

• fileType - String - extension to be used on the file. Ex; json.

Returns a String of the following format: tmp-{random-value}.{fileType}.

const common = require('@asset-pipe/common');
const tmpFile = common.createTemporaryFilename('json');
console.log(tmpFile);

hashArray(arr)

Given an array of hashes, deterministically produces a single hash. Array order is important for determinism.

Arguments:

• arr = string[] - strings to be hashed together to produce a single hash

Returns a promise that will resolve into a hash string.

const { hashArray } = require('@asset-pipe/common');
const hash = await hashArray(['abc1a2b3', 'bac1a2b3', 'ca21a2b3']);
console.log(hash);

Data format

Some of the metods in this module operate on what we call the asset feed. What we refere to as an asset feed is the internal data format used in Browserify. We use the exact same data format as Browserify in the asset-pipe project.

When Browserify resolves CommonJS modules each dependency will be read and transformed into an object which looks something like this:

{
    "id": "c645cf572a8f5acf8716e4846b408d3b1ca45c58",
    "source":
        "\"use strict\";module.exports.world=function(){return\"world\"};",
    "deps": {},
    "file": "./assets/js/bar.js"
}

License

The MIT License (MIT)

Copyright (c) 2017 - Trygve Lie - [email protected]

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.