Creates a function that invokes the method at a given key of an object, optionally prepending any additional supplied parameters to the arguments.
- Return a
function
that usesFunction.prototype.apply()
to bindcontext[fn]
tocontext
. - Use the spread operator (
...
) to prepend any additional supplied parameters to the arguments.
代码实现
const bindKey = (context, fn, ...boundArgs) => (...args) =>
context[fn].apply(context, [...boundArgs, ...args]);
const freddy = {
user: 'fred',
greet: function(greeting, punctuation) {
return greeting + ' ' + this.user + punctuation;
}
};
const freddyBound = bindKey(freddy, 'greet');
console.log(freddyBound('hi', '!')); // 'hi fred!'