Function for adding before/after/call/args/result hooks to another function.
It supports both regular and async functions, even if they may throw.
npm install call-hooksThis function has the following interface:
function callHooks ( fn: Function, hooks: Hooks ): Function;These are the supported hooks:
{
args: ( args: any[] ) => any[],
before: ( args: any[] ) => void,
call: ( args: any[] ) => Result,
result: ( args: any[], result: any ) => any,
after: ( args: any[], result: any | Error ) => void
}Hooks are called in the following order:
The args hook is the first one called, its returned value will be the actual arguments object used:
import hooks from 'call-hooks';
import fn from './my_fn';
const fnWithHooks = hooks ( fn, {
args ( args ) {
if ( args.length === 1 ) return args; // Not overriding the arguments
return [...args, true]; // Overriding the arguments
}
});The before hook is called before the wrapped function will be executed:
import hooks from 'call-hooks';
import fn from './my_fn';
const fnWithHooks = hooks ( fn, {
before ( args ) {
console.log ( 'Called with arguments:', args );
}
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});The call hook is called instead of the wrapped function:
import hooks from 'call-hooks';
import fn from './my_fn';
const fnWithHooks = hooks ( fn, {
call ( args ) {
if ( args.length === 0 ) return null; // Overriding the function
return fn.apply ( this, args ); // Not overriding the function
}
});The result hook is called after the wrapped function has been executed, its returned value will be the actual return value:
import hooks from 'call-hooks';
import fn from './my_fn';
const fnWithHooks = hooks ( fn, {
result ( args, result ) {
if ( isNaN ( result ) ) return 0; // Overriding the returned value
return result; // Not overriding the returned value
}
});The after hook is the last one called:
import hooks from 'call-hooks';
import fn from './my_fn';
const fnWithHooks = hooks ( fn, {
after ( args, result ) {
console.log ( 'Returned result:', result );
}
});MIT © Fabio Spampinato