unassertify

Browserify transform to remove assertions from code. Encourages Design by Contract (DbC).

RELATED MODULES

• unassert: Remove assertions from AST
• babel-plugin-unassert: Babel plugin to remove assertions on build
• webpack-unassert-loader: A webpack loader to remove assertions on production build

INSTALL

$ npm install --save-dev unassertify

HOW TO USE

via CLI

$ $(npm bin)/browserify -t unassertify /path/to/src/target.js > /path/to/build/target.js

via API

var source = require('vinyl-source-stream');
var browserify = require('browserify');
var glob = require('glob'),

gulp.task('production_build', function() {
    var files = glob.sync('./src/*.js');
    var b = browserify({entries: files});
    b.transform('unassertify');
    return b.bundle()
        .pipe(source('bundle.js'))
        .pipe(gulp.dest('./dist'));
});

EXAMPLE

For given math.js below,

'use strict';

var assert = require('assert');

function add (a, b) {
    console.assert(typeof a === 'number');
    assert(!isNaN(a));
    assert.equal(typeof b, 'number');
    assert.ok(!isNaN(b));
    return a + b;
}

Run browserify with -t unassertify to transform file.

$ $(npm bin)/browserify -t unassertify /path/to/demo/math.js > /path/to/build/math.js

You will see assert calls disappear.

'use strict';
function add(a, b) {
    return a + b;
}

SUPPORTED PATTERNS

Assertion expressions are removed when they match patterns below. In other words, unassertify removes assertion calls that are compatible with Node.js standard assert API (and console.assert).

• assert(value, [message])
• assert.ok(value, [message])
• assert.equal(actual, expected, [message])
• assert.notEqual(actual, expected, [message])
• assert.strictEqual(actual, expected, [message])
• assert.notStrictEqual(actual, expected, [message])
• assert.deepEqual(actual, expected, [message])
• assert.notDeepEqual(actual, expected, [message])
• assert.deepStrictEqual(actual, expected, [message])
• assert.notDeepStrictEqual(actual, expected, [message])
• assert.fail(actual, expected, message, operator)
• assert.throws(block, [error], [message])
• assert.doesNotThrow(block, [message])
• assert.ifError(value)
• console.assert(value, [message])

unassertify also removes assert variable declarations,

• var assert = require("assert")
• var assert = require("power-assert")

and assignments.

• assert = require("assert")
• assert = require("power-assert")

AUTHOR

• Takuto Wada

LICENSE

Licensed under the MIT license.