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https://github.com/rayzr522/method-inject
A simple system for injecting and transforming methods
https://github.com/rayzr522/method-inject
Last synced: 26 days ago
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A simple system for injecting and transforming methods
- Host: GitHub
- URL: https://github.com/rayzr522/method-inject
- Owner: rayzr522
- License: mit
- Created: 2018-01-18T00:28:28.000Z (almost 7 years ago)
- Default Branch: master
- Last Pushed: 2023-12-22T01:27:47.000Z (11 months ago)
- Last Synced: 2024-04-23T23:15:20.290Z (7 months ago)
- Language: JavaScript
- Size: 3.91 KB
- Stars: 1
- Watchers: 3
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# method-inject
> A simple system for injecting and transforming methods
## Installation
```bash
yarn add method-inject
```
```bash
npm install --save method-inject
```
## Usage
To use method-inject, it's as simple as calling it on a method:
```javascript
const inject = require("method-inject");
// Transform the first argument and prepend '[INFO] ' to it
const log = inject(console.log).transform(0, (text) => "[INFO] " + text);
log("Hello, there!");
// => [INFO] Hello, there!
```
There are several methods, the rest of which are shown below:
```javascript
const inject = require("method-inject");
const someObject = {
buggedMethod(someArg) {
console.log(someArg + 1);
},
};
// Hmm, we've been getting `NaN` in the console from someObject.buggedMethod, let's check it out:
someObject.buggedMethod = inject(someObject.buggedMethod, someObject).before(
(args) => console.log("buggedMethod called with the following args:", args)
);
// Note that we passed someObject as the second parameter to inject, indicating that the method should be bound to that object.
// Problem code:
someObject.buggedMethod("ERRORS");
// => buggedMethod called with the following args: [ 'ERRORS' ]
// => NaN
```
```javascript
const inject = require('method-inject');
const db = {
internal: {
life: 42
},
get(key, default) {
return this.internal[key] || default;
}
};
if (process.env.DB_VERBOSE) {
db.get = inject(db.get, db).after((returnValue, args) => {
console.log(`DB::GET(key=${args[0]},default=${args[1] || 'none'}) -> ${returnValue}`);
});
}
// Assuming DB_VERBOSE=true:
console.log(`The meaning of life is ${db.get('life', -1)}`);
// => DB::GET(key=life,default=-1) -> 42
// => The meaning of life is 42
```
```javascript
const inject = require("method-inject");
const multiply = (a, b) => {
return a * b;
};
const multiplyAndSquare = inject(multiply).transformOutput(
(output) => output * output
);
// (2 * 3) * (2 * 3) = 6 * 6 = 36
console.log(multiplyAndSquare(2, 3));
// => 36
```
Methods can also be chained indefinitely:
```javascript
const inject = require("method-inject");
const multiply = (a, b) => a * b;
const addOne = (x) => x + 1;
const square = (x) => x * x;
const verboseComplexMath = inject(multiply)
.after((output) => console.log(`COMPLEX_CALC -> ${output}`))
.transformOutput(addOne)
.transformOutput(square);
console.log(verboseComplexMath(4, 5));
// => COMPLEX_CALC -> 441
// => 441
```