https://github.com/pgilad/check-constants
Find numbers and strings that should be extracted as a declaration statement
https://github.com/pgilad/check-constants
Last synced: about 1 year ago
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Find numbers and strings that should be extracted as a declaration statement
- Host: GitHub
- URL: https://github.com/pgilad/check-constants
- Owner: pgilad
- License: mit
- Created: 2014-07-26T15:14:40.000Z (almost 12 years ago)
- Default Branch: master
- Last Pushed: 2015-05-22T17:24:22.000Z (about 11 years ago)
- Last Synced: 2025-04-20T09:39:47.452Z (about 1 year ago)
- Language: JavaScript
- Homepage: https://github.com/pgilad/check-constants
- Size: 949 KB
- Stars: 14
- Watchers: 3
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: readme.md
- License: LICENSE
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README
# check-constants
> Find numbers and strings that should be extracted as a declaration statement
[](https://npmjs.org/package/check-constants)
[](https://npmjs.org/package/check-constants)
[](https://travis-ci.org/pgilad/check-constants)
The idea behind this project is that numbers and strings should be extracted as declared constants (or vars), so that they could be easily controlled & changed.
Imagine that you have a function which will calculate the total sum owed after taxes:
```js
//basic.js
function getTotal(subtotal) {
var beforeTax = subtotal + 9.99;
return beforeTax + (beforeTax * 0.13);
}
```
As you can see, in a month from now, and in a large code base, we might not remember what are those `9.99` and `0.13`, and
also, suppose we have several instances of the number `0.13` and we want to change it? Now you need to refactor
all occurrences hoping you didn't miss anything or over-do it.
`check-constants` will find the numbers that you should extract as a declaration statement:
The example above, could be re-factored to:
```js
//corrected.js
var FIXED_COST = 9.99;
var TAX = 0.13;
function getTotal(subtotal) {
var beforeTax = subtotal + FIXED_COST;
return beforeTax + (beforeTax * TAX);
}
```
Now let's see what happens when we run `check-constants` on the corrected file:
This project uses [Rocambole](https://github.com/millermedeiros/rocambole) to parse your JS,
and it's a simplified version of [buddy.js](https://github.com/danielstjules/buddy.js) which I found overcomplicated and too heavy.
## Usage
### Command Line
#### Installation
```bash
$ npm install --global check-constants
```
#### Examples
```bash
# show the help menu
❯ check-constants --help
Usage: check-constants [options]
Options:
-h, --help output usage information
-V, --version output the version number
-e, --enforce-const require literals to be defined using const
-i, --ignore list numbers to ignore (default: 0,1)
-I, --disable-ignore disables the ignore list
-s, --strings check strings as well
-m, --min-length [minLength] minimum length of strings to be checked [0]
-r, --reporter [reporter] specify the reporter to use [table|json] (default: table)
Examples:
$ check-constants index.js
$ check-constants --reporter json index.js
$ cat index.js | check-constants
# Easily check a file by path
$ check-constants file.js
# Check files by using glob pattern
$ check-constants js/**/*.js
# Check a file by piping it
$ cat file.js | check-constants
# Format output as json
$ check-constants file.js --reporter json
# Override ignored numbers
$ check-constants file.js --ignore 1,5,13
# Disable default ignored numbers (0,1)
$ check-constants file.js --disable-ignore
# Make sure variables are declared as const
$ check-constants --enforce-const file.js
# Check the current version of the cli app
$ check-constants --version
```
### Programmatic
#### Installation
```bash
$ npm install --save-dev check-constants
```
#### Examples
```js
var fs = require('fs');
var checkConstants = require('check-constants');
var options = {};
var contents = fs.readFileSync('./contents.js', 'utf8');
var errors = checkConstants.inspect(contents, options);
// -> errors will contain possible variables that need extraction
```
### Build Time
`check-constants` can also be used in conjunction with other javascript build systems, such as:
* [gulp-check-constants](https://github.com/pgilad/gulp-check-constants)
* [grunt-check-constants](https://github.com/pgilad/grunt-check-constants)
## The Output
```js
[{
"file": "index.js",
"code": "i = i + 2",
"value": 2,
"loc": {
"start": {
"line": 5,
"column": 28
},
"end": {
"line": 5,
"column": 29
}
}
}]
```
## API
`check-constants` exposes the following API:
### .inspect(contents, options)
#### contents
`String` - the contents to check
#### options
Options is an optional object containing the following properties:
##### strings
Type: `Boolean`
Default: `false`
Whether to check for strings as well as numbers.
##### minLength
Type: `Number`
Default: `0`
Only used when option `strings` is true. Limits the minimum string length checking.
##### enforceConst
Type: `Boolean`
Default: `false`
Whether to enforce declarations to be used with `const`.
##### ignore
Type: `Array`
Default: `[0, 1]`
Strings and numbers to ignore
##### file
Type: `String`
Default: `null`
Filename being checked if available (i.e not from a stream). Will be attached
to the result object.
### .log\[reporter](results)
#### reporter
Which reporter to use. Currently supported `json` and `table`.
#### results
The resulting object from `.inspect()`
## License
MIT ©[Gilad Peleg](http://giladpeleg.com)