node-file-eval

node-file-eval
==============

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[npm]: https://www.npmjs.org/package/node-file-eval
[npm-img]: https://img.shields.io/npm/v/node-file-eval.svg

[travis]: https://travis-ci.org/node-eval/node-file-eval
[test-img]: https://img.shields.io/travis/node-eval/node-file-eval/master.svg?label=tests

[coveralls]: https://coveralls.io/r/node-eval/node-file-eval
[coverage-img]: https://img.shields.io/coveralls/node-eval/node-file-eval/master.svg

[david]: https://david-dm.org/node-eval/node-file-eval
[david-img]: http://img.shields.io/david/node-eval/node-file-eval/master.svg

Read file and eval it. Uses node-eval.

Like require, but asynchronous and doesn't use the module cache.

Important: internally node-file-eval will resolve passed relative paths with path.resolve(), not require.resolve().

Install
-------

``
$ npm install --save node-file-eval
`

Usage
-----

`js
const nodeFileEval = require('node-file-eval');

fileEval('./path/to/file.js')
.then(console.log)
.catch(console.log);
`

API
---

$3

$3

Type: string.

The filename or file descriptor.

The node-file-eval determinate format by extension. If filename ends with .json extention, its contents will be parsing with JSON.parse. If filename ends with .js, its contents will be evaluating with vm.

By default expected JS-expression or CommonJS module contents.

#### options

Type: Object, string.

Options or encoding.

#### options.encoding

Type: string.

Default: utf-8.

The file encoding.

#### options.flag

Type: string.

Default: r.

The flag mode.

#### options.context

Type: Object.

The object to provide into execute method.

If context is specified, then module contents will be evaluating with vm.runInNewContext.

If context is not specified, then module contents will be evaluating with vm.runInThisContext.

With context you can provide some like-a-global variables into node-file-eval.

`js
const nodeFileEval = require('node-file-eval');

const secretKey = '^___^';
const contents = 'module.exports = secretKey;';

// The file has the contents "module.exports = secretKey;"
nodeFileEval('./path/to/file.js', {
context: { secretKey }
});

// ➜ '^___^'
`

$3

Synchronous version of nodeFileEval.

Method signature is same.

Formats
-------

Supports CommonJS and JSON formats.

> See examples with evaluating files with different formats.

$3

Evaluates CommonJS files with .js extention.

`js
const nodeFileEval = require('node-file-eval');

// export data with module.exports or exports
nodeFileEval('./path/to/file.js');
`

$3

Evaluates JSON files with .json extention.

`js
const nodeFileEval = require('node-file-eval');

nodeFileEval('./path/to/file.json');
``

Related
-------

* node-eval — eval Node.js contents only (JS-expression, CommonJS modules and JSON).
* any-eval — eval any contents (JS-expression, CommonJS modules and JSON/JSON5).
* file-eval — read any file and eval it with any-eval.

License
-------

MIT © Andrew Abramov