empower

Power Assert feature enhancer for assert function/object.

DESCRIPTION

empower is a core module of power-assert family. empower enhances standard assert function or any assert-like object to work with power-assert feature added code instrumented by espower.

empower works with standard assert function (best fit with Mocha), and also supports assert-like objects/functions provided by various testing frameworks such as QUnit, buster.js, and nodeunit.

Pull-requests, issue reports and patches are always welcomed. See power-assert project for more documentation.

CHANGELOG

See CHANGELOG

API

var enhancedAssert = empower(originalAssert, formatter, [options])

return type
function or object

empower function takes function or object(originalAssert) and formatter function created by power-assert-formatter then returns PowerAssert feature added function/object base on originalAssert. If destructive option is falsy, originalAssert will be unchanged. If destructive option is truthy, originalAssert will be manipulated directly and returned enhancedAssert will be the same instance of originalAssert.

originalAssert

type	default value
function or object	N/A

originalAssert is an instance of standard assert function or any assert-like object. see SUPPORTED ASSERTION LIBRARIES and ASSERTION LIBRARIES KNOWN TO WORK section. Be careful that originalAssert will be manipulated directly if destructive option is truthy.

formatter

type	default value
function	N/A

formatter function created by power-assert-formatter.

options

type	default value
object	(return value of empower.defaultOptions())

Configuration options. If not passed, default options will be used.

options.destructive

type	default value
boolean	false

If truthy, modify originalAssert destructively.

If false, empower mimics originalAssert as new object/function, so originalAssert will not be changed. If true, originalAssert will be manipulated directly and returned enhancedAssert will be the same instance of originalAssert.

options.modifyMessageOnRethrow

type	default value
boolean	false

If truthy, modify message property of AssertionError on rethrow.

options.saveContextOnRethrow

type	default value
boolean	false

If truthy, add powerAssertContext property to AssertionError on rethrow.

modifyMessageOnRethrow option and saveContextOnRethrow option makes behavior matrix as below.

modifyMessageOnRethrow	saveContextOnRethrow	resulting behavior
false (default)	false (default)	Always modify assertion message argument directly
true	false	Modify message of AssertionError on fail
false	true	Do not modify message of AssertionError but add powerAssertContext property on fail
true	true	On fail, modify message of AssertionError and also add powerAssertContext property

options.patterns

type	default value
Array of string	objects shown below

[
    '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])'
]

Target patterns for power assert feature instrumentation.

Pattern detection is done by escallmatch. Any arguments enclosed in bracket (for example, [message]) means optional parameters. Without bracket means mandatory parameters.

var options = empower.defaultOptions();

Returns default options object for empower function. In other words, returns

{
    destructive: false,
    modifyMessageOnRethrow: false,
    saveContextOnRethrow: false,
    patterns: [
        '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])'
    ]
}

SUPPORTED ASSERTION LIBRARIES

• Node assert API
• Jxck/assert

ASSERTION LIBRARIES KNOWN TO WORK

• QUnit.assert
• nodeunit
• buster-assertions

INSTALL

via npm

Install

$ npm install --save-dev empower

use empower npm module on browser

empower function is exported

<script type="text/javascript" src="./path/to/node_modules/empower/build/empower.js"></script>

via bower

Install

$ bower install --save-dev empower

Then load (empower function is exported)

<script type="text/javascript" src="./path/to/bower_components/empower/build/empower.js"></script>

OUR SUPPORT POLICY

We support Node under maintenance. In other words, we stop supporting old Node version when their maintenance ends.

We also support "modern enough" browsers such as Chrome, Firefox, Safari, Edge etc.

Any other environments are not supported officially (means that we do not test against them on CI service). empower is known to work with old browsers, and trying to keep them working though.

AUTHOR

• Takuto Wada

CONTRIBUTORS

• James Talmage (jamestalmage)

LICENSE

Licensed under the MIT license.