gulp-replace-task

Replace text patterns with applause.

Install

From NPM:

npm install gulp-replace-task --save-dev

Replace Task

Assuming installation via NPM, you can use gulp-replace-task in your gulpfile like this:

var gulp = require('gulp');
var replace = require('gulp-replace-task');

gulp.task('default', function () {
  gulp.src('src/index.html')
    .pipe(replace({
      patterns: [
        {
          match: 'foo',
          replacement: 'bar'
        }
      ]
    }))
    .pipe(gulp.dest('build'));
});

Options

patterns

Type: Array

Define patterns that will be used to replace the contents of source files.

patterns.match

Type: String|RegExp

Indicates the matching expression.

If matching type is String we use a simple variable lookup mechanism @@string (in any other case we use the default regexp replace logic):

{
  patterns: [
    {
      match: 'foo',
      replacement: 'bar'  // replaces "@@foo" to "bar"
    }
  ]
}

patterns.replacement or patterns.replace

Type: String|Function|Object

Indicates the replacement for match, for more information about replacement check out the String.replace.

You can specify a function as replacement. In this case, the function will be invoked after the match has been performed. The function's result (return value) will be used as the replacement string.

{
  patterns: [
    {
      match: /foo/g,
      replacement: function () {
        return 'bar'; // replaces "foo" to "bar"
      }
    }
  ]
}

Also supports object as replacement (we create string representation of object using JSON.stringify):

{
  patterns: [
    {
      match: /foo/g,
      replacement: [1, 2, 3] // replaces "foo" with string representation of "array" object
    }
  ]
}

The replacement only resolve the special replacement patterns when using regexp for matching.

patterns.json

Type: Object

If an attribute json is found in pattern definition we flatten the object using delimiter concatenation and each key–value pair will be used for the replacement (simple variable lookup mechanism and no regexp support).

{
  patterns: [
    {
      json: {
        "key": "value" // replaces "@@key" to "value"
      }
    }
  ]
}

Also supports nested objects:

{
  patterns: [
    {
      json: {
        "key": "value",   // replaces "@@key" to "value"
        "inner": {        // replaces "@@inner" with string representation of "inner" object
          "key": "value"  // replaces "@@inner.key" to "value"
        }
      }
    }
  ]
}

For deferred invocations is possible to define functions:

{
  patterns: [
    {
      json: function (done) {
        done({
          key: 'value'
        });
      }
    }
  ]
}

patterns.yaml

Type: String

If an attribute yaml found in pattern definition it will be converted and then processed like json attribute.

{
  patterns: [
    {
      yaml: 'key: value'  // replaces "@@key" to "value"
    }
  ]
}

For deferred invocations is possible to define functions:

{
  patterns: [
    {
      yaml: function (done) {
        done('key: value');
      }
    }
  ]
}

patterns.cson

Type: String

If an attribute cson is found in pattern definition it will be converted and then processed like json attribute.

{
  patterns: [
    {
      cson: 'key: \'value\''
    }
  ]
}

For deferred invocations is possible to define functions:

{
  patterns: [
    {
      cson: function (done) {
        done('key: \'value\'');
      }
    }
  ]
}

variables

Type: Object

This is the old way to define patterns using plain object (simple variable lookup mechanism and no regexp support). You can still use this but for more control you should use the new patterns way.

{
  variables: {
    'key': 'value' // replaces "@@key" to "value"
  }
}

prefix

Type: String Default: @@

The prefix added for matching (prevent bad replacements / easy way).

This only applies for simple variable lookup mechanism.

usePrefix

Type: Boolean Default: true

If set to false, we match the pattern without prefix concatenation (useful when you want to lookup a simple string).

This only applies for simple variable lookup mechanism.

preservePrefix

Type: Boolean Default: false

If set to true, we preserve the prefix in target.

This only applies for simple variable lookup mechanism and when patterns.replacement is a string.

delimiter

Type: String Default: .

The delimiter used to flatten when using object as replacement.

preserveOrder

Type: Boolean Default: false

If set to true, we preserve the patterns definition order, otherwise these will be sorted (in ascending order) to prevent replacement issues like head / header (typo regexps will be resolved at last).

detail

Type: Boolean Default: false

If set to true, return an object response with the content and detail of replace operation.

Usage Examples

Basic

File src/manifest.appcache:

CACHE MANIFEST
# @@timestamp

CACHE:

favicon.ico
index.html

NETWORK:
*

Gulpfile:

gulp.task('default', function () {
  gulp.src('src/manifest.appcache')
    .pipe(replace({
      patterns: [
        {
          match: 'timestamp',
          replacement: new Date().getTime()
        }
      ]
    }))
    .pipe(gulp.dest('build'));
});

Multiple matching

File src/manifest.appcache:

CACHE MANIFEST
# @@timestamp

CACHE:

favicon.ico
index.html

NETWORK:
*

File src/humans.txt:

              __     _
   _    _/__  /./|,//_`
  /_//_// /_|///  //_, outaTiME v.@@version

/* TEAM */
  Web Developer / Graphic Designer: Ariel Oscar Falduto
  Site: http://www.outa.im
  Twitter: @outa7iME
  Contact: afalduto at gmail dot com
  From: Buenos Aires, Argentina

/* SITE */
  Last update: @@timestamp
  Standards: HTML5, CSS3, robotstxt.org, humanstxt.org
  Components: H5BP, Modernizr, jQuery, Twitter Bootstrap, LESS, Jade, Grunt
  Software: Sublime Text 2, Photoshop, LiveReload

Gulpfile:

var pkg = require('./package.json');
gulp.task('default', function () {
  gulp.src(['src/manifest.appcache', 'src/humans.txt'])
    .pipe(replace({
      patterns: [
        {
          match: 'version',
          replacement: pkg.version
        },
        {
          match: 'timestamp',
          replacement: new Date().getTime()
        }
      ]
    }))
    .pipe(gulp.dest('build'));
});

Cache busting

File src/index.html:

<head>
  <link rel="stylesheet" href="/css/style.css?rel=@@timestamp">
  <script src="/js/app.js?rel=@@timestamp"></script>
</head>

Gulpfile:

gulp.task('default', function () {
  gulp.src('src/index.html')
    .pipe(replace({
      patterns: [
        {
          match: 'timestamp',
          replacement: new Date().getTime()
        }
      ]
    }))
    .pipe(gulp.dest('build'));
});

Include file

File src/index.html:

<body>
  @@include
</body>

Gulpfile:

var fs = require('fs');
gulp.task('default', function () {
  gulp.src('src/index.html')
    .pipe(replace({
      patterns: [
        {
          match: 'include',
          replacement: fs.readFileSync('./includes/content.html', 'utf8')
        }
      ]
    }))
    .pipe(gulp.dest('build'));
});

Regular expression

File src/username.txt:

John Smith

Gulpfile:

gulp.task('default', function () {
  gulp.src('src/username.txt')
    .pipe(replace({
      patterns: [
        {
          match: /(\w+)\s(\w+)/,
          replacement: '$2, $1' // replaces "John Smith" to "Smith, John"
        }
      ]
    }))
    .pipe(gulp.dest('build'));
});

Lookup for foo instead of @@foo

Gulpfile:

gulp.task('default', function () {
  gulp.src('src/foo.txt')

    // option 1 (explicitly using an regexp)
    .pipe(replace({
      patterns: [
        {
          match: /foo/g,
          replacement: 'bar'
        }
      ]
    }))

    // option 2 (easy way)
    .pipe(replace({
      patterns: [
        {
          match: 'foo',
          replacement: 'bar'
        }
      ],
      usePrefix: false
    }))

    // option 3 (old way)
    .pipe(replace({
      patterns: [
        {
          match: 'foo',
          replacement: 'bar'
        }
      ],
      prefix: '' // remove prefix
    }))

    .pipe(gulp.dest('build'));
});

Release History

• 2015-09-09   v0.11.0   Improvements in handling patterns. Fix plain object representation issue. More test cases.
• 2015-08-19   v0.10.0   Last applause integration and package.json update.
• 2015-08-06   v0.2.3   Fix issue with special characters attributes ($$, $&, $`, $', $n or $nn) on JSON, YAML and CSON.
• 2015-05-07   v0.2.1   Fix regression issue with empty string in replacement.
• 2015-05-01   v0.2.0   Update to applause v0.4.0.
• 2014-10-10   v0.1.0   Escape regexp when matching type is String.
• 2014-06-10   v0.0.6   Remove node v.8.0 support and third party dependencies updated.
• 2014-04-20   v0.0.5   JSON / YAML / CSON as function supported. Readme updated (thanks @milanlandaverde).
• 2014-03-23   v0.0.4   Readme updated.
• 2014-03-22   v0.0.3   Modular core renamed to applause. Performance improvements. Expression flag removed. New pattern matching for CSON object. More test cases, readme updated and code cleanup.
• 2014-03-21   v0.0.2   Readme updated and code cleanup.
• 2014-03-20   v0.0.1   Initial version.

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Task submitted by Ariel Falduto