68 lines
1.9 KiB
Markdown
68 lines
1.9 KiB
Markdown
# is-expression
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Validates a string as a JavaScript expression
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[](https://travis-ci.org/pugjs/is-expression)
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[](https://david-dm.org/pugjs/is-expression)
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[](https://rollingversions.com/pugjs/is-expression)
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[](https://www.npmjs.org/package/is-expression)
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## Installation
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npm install is-expression
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## Usage
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### `isExpression(src[, options])`
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Validates a string as a JavaScript expression.
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`src` contains the source.
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`options` can contain any Acorn options (since we use Acorn under-the-hood),
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or any of the following:
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- `throw`: Throw an error if the string is not an expression. The error can
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be an Acorn error, with location information in `err.loc` and `err.pos`.
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Defaults to `false`.
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- `strict`: Use strict mode when trying to parse the string. Defaults to
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`false`. Even if this option is `false`, if you have provided
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`options.sourceType === 'module'` which imples strict mode under ES2015,
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strict mode will be used.
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- `lineComment`: When `true`, allows line comments in the expression.
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Defaults to `false` for safety.
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See the examples below for usage.
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## Examples
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```js
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var isExpression = require('is-expression')
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isExpression('myVar')
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//=> true
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isExpression('var')
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//=> false
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isExpression('["an", "array", "\'s"].indexOf("index")')
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//=> true
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isExpression('var', {throw: true})
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// SyntaxError: Unexpected token (1:0)
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// at Parser.pp.raise (acorn/dist/acorn.js:940:13)
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// at ...
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isExpression('public')
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//=> true
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isExpression('public', {strict: true})
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//=> false
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isExpression('abc // my comment')
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//=> false
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isExpression('abc // my comment', {lineComment: true})
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//=> true
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```
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## License
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MIT
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