Hot method patching framework for handling environmental method differences
npm install hot-patcher!Build status 
Hot-Patcher provides a simple API to manage patched methods. I found while writing Buttercup that managing overwritten methods between environments (Node/Browser/React-Native) was becoming cumbersome, and having a single _agreed-upon_ method of doing so was the best way to go.
Install Hot-Patcher from npm:
``shell`
npm install hot-patcher --save
NB: This is an ESM library.
Hot-Patcher is a class and can simply be instantiated:
`typescript
import { HotPatcher } from "hot-patcher";
const hp = new HotPatcher();
`
Hot-Patcher is designed to be used with patchable tools:
`typescript
import { HotPatcher } from "hot-patcher";
export class MyHelper {
public patcher: HotPatcher;
constructor() {
this.patcher = new HotPatcher();
}
increment(arg: number): number {
return this.patcher.patchInline
return someArg + 1;
}, arg);
}
}
`
You can then patch methods when required:
`typescript
import { MyHelper } from "./MyHelper.js";
export function getHelper() {
const helper = new MyHelper();
helper.patch("increment", (val: number) => val + 2);
return helper;
}
`
Patched methods can easily be fetched later:
`typescript
import { getSharedPatcher } from "./patching.js";
const randomString = getSharedPatcher().get("randomString");
randomString(5); // Generates a random string
// Or, execute the method directly:
getSharedPatcher().execute("randomString", 5) // Generates a random string
`
You can check if a method is patched by using isPatched: patcher.isPatched("some method").
Ideally you could wrap function implementation with a patch call, executing it on demand:
`typescript
function add(a: number, b: number): number {
return patcher.patchInline("add", (a, b) => a + b, a, b);
}
patcher.isPatched("add"); // false
add(1, 2); // 3
patcher.isPatched("add"); // true
// calling add() multiple times will call the patched method without "re-patching" it
// over and over again..
`
You can use Hot-Patcher to create sequences of functions:
`typescript
patcher.plugin("increment", x => x 2, x => x 2);
patcher.execute("increment", 2); // 8
`
Which is basically syntactic sugar for a regular patch() call:
`typescript
patcher
.patch("increment", x => x * 2, { chain: true })
.patch("increment", x => x * 2, { chain: true });
patcher.execute("increment", 2); // 8
`
Executing a regular patch() without chain: true will overwrite all chained methods with the new method.
Calling patch() with chain: true when a method already exists will simply add the new method after the existing:
`typescriptchain
patcher
.patch("increment", x => x * 2, { chain: false }) // or simply without specified
.patch("increment", x => x * 2, { chain: true });
patcher.execute("increment", 2); // still 8
`
method:`typescript
const methodA = () => {};
const methodB = () => {};patcher
// methodA is now the current (and original)
.patch("someMethod", methodA)
// methodB is now the current
.patch("someMethod", methodB);
// Restore "someMethod" to methodA (original)
patcher.restore("someMethod");
``The intention of Hot-Patcher is not to push every method into a patching instance, but to provide a common API for specific methods which _require_ patching in some specific environments or in situations where users/consumers are expected to provide their own custom implementations.