You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
43 lines
1.8 KiB
Markdown
43 lines
1.8 KiB
Markdown
5 years ago
|
# constantinople
|
||
|
|
|
||
|
|
Determine whether a JavaScript expression evaluates to a constant (using acorn). Here it is assumed to be safe to underestimate how constant something is.
|
||
|
|
|
||
|
|
[](https://travis-ci.org/ForbesLindesay/constantinople)
|
||
|
|
[](https://gemnasium.com/ForbesLindesay/constantinople)
|
||
|
|
[](https://www.npmjs.org/package/constantinople)
|
||
|
|
|
||
|
|
## Installation
|
||
|
|
|
||
|
|
npm install constantinople
|
||
|
|
|
||
|
|
## Usage
|
||
|
|
|
||
|
|
```js
|
||
|
|
var isConstant = require('constantinople')
|
||
|
|
|
||
|
|
if (isConstant('"foo" + 5')) {
|
||
|
|
console.dir(isConstant.toConstant('"foo" + 5'))
|
||
|
|
}
|
||
|
|
if (isConstant('Math.floor(10.5)', {Math: Math})) {
|
||
|
|
console.dir(isConstant.toConstant('Math.floor(10.5)', {Math: Math}))
|
||
|
|
}
|
||
|
|
```
|
||
|
|
|
||
|
|
## API
|
||
|
|
|
||
|
|
### isConstant(src, [constants])
|
||
|
|
|
||
|
|
Returns `true` if `src` evaluates to a constant, `false` otherwise. It will also return `false` if there is a syntax error, which makes it safe to use on potentially ES6 code.
|
||
|
|
|
||
|
|
Constants is an object mapping strings to values, where those values should be treated as constants. Note that this makes it a pretty bad idea to have `Math` in there if the user might make use of `Math.random` and a pretty bad idea to have `Date` in there.
|
||
|
|
|
||
|
|
### toConstant(src, [constants])
|
||
|
|
|
||
|
|
Returns the value resulting from evaluating `src`. This method throws an error if the expression is not constant. e.g. `toConstant("Math.random()")` would throw an error.
|
||
|
|
|
||
|
|
Constants is an object mapping strings to values, where those values should be treated as constants. Note that this makes it a pretty bad idea to have `Math` in there if the user might make use of `Math.random` and a pretty bad idea to have `Date` in there.
|
||
|
|
|
||
|
|
## License
|
||
|
|
|
||
|
|
MIT
|