power-assert-context-formatter

[![power-assert][power-assert-banner]][power-assert-url]

[![Build Status][travis-image]][travis-url]
[![NPM version][npm-image]][npm-url]
[![License][license-image]][license-url]

Create function to format powerAssertContext object provided by power-assert at runtime.

USAGE
---------------------------------------

``javascript
var createFormatter = require('power-assert-context-formatter');
var FileRenderer = require('power-assert-renderer-file');
var AssertionRenderer = require('power-assert-renderer-assertion');
var DiagramRenderer = require('power-assert-renderer-diagram');
var ComparisonRenderer = require('power-assert-renderer-comparison');

var format = createFormatter({
renderers: [
FileRenderer,
AssertionRenderer,
DiagramRenderer,
ComparisonRenderer
]
});

var assert = require('assert');

var foo = 'foo';
var bar = 'bar';
try {
assert(foo === bar);
} catch (e) {
var formattedText = format(e.powerAssertContext);
. . .
}
`


API
---------------------------------------

$3

| return type |
|:------------|
| function |

Returns creator function of formatter.

$3

| return type |
|:------------|
| function |

Create format function to format powerAssertContext object provided by power-assert.


#### options.renderers

| type | default value |
|:---------------------------------------------|:--------------|
| Array of function or Array of object | null |

Array of constructor function of various Renderers.
Each Renderer is instantiated for each assertion and registered to ContextTraversal.

##### customization

Each renderer accepts its options via form of object literal.

`javascript
var format = createFormatter({
renderers: [
{ ctor: FileRenderer },
{ ctor: AssertionRenderer },
{ ctor: DiagramRenderer, options: { maxDepth: 2 } },
{ ctor: ComparisonRenderer, options: { lineDiffThreshold: 3 } }
]
});
`


#### options.reducers

| type | default value |
|:----------------------|:--------------|
| Array of function | empty array |

Array of reducer function to be applied to powerAssertContext.


#### options.outputOffset

| type | default value |
|:---------|:--------------|
| number | 2 |

Number of spaces inserted at the left in power-assert output.


#### options.lineSeparator

| type | default value |
|:---------|:--------------|
| string | "\n" |

Line separator in power assert output.


#### options.legacy

| type | default value |
|:----------|:--------------|
| boolean | false |

When true, new renderers and legacy renderer implementations can be used together.

$3

| return type |
|:------------|
| string |

Format powerAssertContext into formattedText. powerAssertContext is an internal object structure, containing informations to render. Example of powerAssertContext is:

`javascript
{
source: {
content: 'assert(foo === bar)',
filepath: 'test/some_test.js',
line: 1,
ast: '### JSON representation of AST nodes ###',
tokens: '### JSON representation of AST tokens ###',
visitorKeys: '### JSON representation of AST visitor keys ###'
},
args: [
{
value: false,
events: [
{
value: "FOO",
espath: "arguments/0/left"
},
{
value: "BAR",
espath: "arguments/0/right"
},
{
value: false,
espath: "arguments/0"
}
]
}
]
}
`


INSTALL
---------------------------------------

`sh
$ npm install --save-dev power-assert-context-formatter
``

AUTHOR
---------------------------------------
* Takuto Wada

LICENSE
---------------------------------------
Licensed under the MIT license.

[power-assert-url]: https://github.com/power-assert-js/power-assert
[power-assert-banner]: https://raw.githubusercontent.com/power-assert-js/power-assert-js-logo/master/banner/banner-official-fullcolor.png

[travis-url]: https://travis-ci.org/twada/power-assert-runtime
[travis-image]: https://secure.travis-ci.org/twada/power-assert-runtime.svg?branch=master

[npm-url]: https://npmjs.org/package/power-assert-context-formatter
[npm-image]: https://badge.fury.io/js/power-assert-context-formatter.svg

[license-url]: https://github.com/twada/power-assert-runtime/blob/master/LICENSE
[license-image]: https://img.shields.io/badge/license-MIT-brightgreen.svg