gulp-iife

A Gulp plugin for wrapping JavaScript code within immediately invoked function expressions (IIFEs).

Install

$ npm install --save-dev gulp-iife

Usage

var gulp = require("gulp");
var iife = require("gulp-iife");

gulp.task("default", function() {
  return gulp.src("src/input.js")
    .pipe(iife())
    .pipe(gulp.dest("dist"));
});

Input file:

var greeting = "Hello, World!";
console.log(greeting);

Output file:

;(function() {
"use strict";

var greeting = "Hello, World!";
console.log(greeting);
}());

Options

You can configure the following options:

• useStrict
• trimCode
• prependSemicolon
• bindThis
• params
• args

Here's an example specifying all available options:

var gulp = require("gulp");
var iife = require("gulp-iife");

gulp.task("default", function() {
  return gulp.src("src/input.js")
    .pipe(iife({
      useStrict: true,
      trimCode: true,
      prependSemicolon: false,
      bindThis: false,
      params: ["window", "document", "$", "undefined"],
      args: ["window", "document", "jQuery"]
    }))
    .pipe(gulp.dest("dist"));
});

Input file:

var greeting = "Hello, World!";
console.log(greeting);

Output file:

(function(window, document, $, undefined) {
"use strict";

var greeting = "Hello, World!";
console.log(greeting);
}(window, document, jQuery));

useStrict

A boolean indicating whether to prepend a "use strict"; directive to the function body.

• Default: true

trimCode

A boolean indicating whether to remove leading & trailing whitespace from the code.

• Default: true

prependSemicolon

A boolean indicating whether to prepend a semicolon as statement terminator before the IIFE.

• Default: true

bindThis

A boolean indicating whether to append .bind(this) to the IIFE. Setting this value to true makes the surrounding global object available to the function, which is usually not the case in strict mode.

• Default: false

params

An array of parameter names to be accepted by the IIFE. If the args option is not specified, the same identifiers will be passed as arguments of the function call.

• Default: none

args

An array of argument names to be passed into the IIFE. If the params option is not specified, the parameters of the function will have the same names as the arguments passed.

• Default: none

Source Maps

gulp-iife supports source maps, which means you can use it like this:

var gulp = require("gulp");
var iife = require("../gulp-iife/lib");
var sourcemaps = require("gulp-sourcemaps");

gulp.task("default", function() {
  return gulp.src("src/input.js")
    .pipe(sourcemaps.init())
    .pipe(iife({ }))
    .pipe(sourcemaps.write("./"))
    .pipe(gulp.dest("./built"));
});

Changelog

The changelog can be found in CHANGELOG.md.

Formatting

In the spirit of Gulp plugins, gulp-iife does one thing and one thing only: adding wrapping IIFEs.

If you'd like the resulting code to be neatly indented or otherwise formatted, pipe the output to another Gulp plugin which formats the JavaScript code, such as gulp-esformatter.