2693-call-function-with-custom-context

2693. Call Function with Custom Context (Medium) (https://leetcode.com/problems/call-function-with-custom-context/)

Enhance all functions to have the callPolyfill method. The method accepts an object obj as its first parameter and any number of additional arguments. The obj becomes the this context for the function. The additional arguments are passed to the function that the callPolyfill method belongs on. Please solve it without using the built-in Function.call method. Constraints: - typeof args[0] == “object” and args[0] != null - 1 <= args.length <= 100 - 2 <= JSON.stringify(args[0]).length <= 10

type JSONValue = null | boolean | number | string | JSONValue[] | { [key: string]: JSONValue }
 
interface Function {
  callPolyfill: (context: Record<string, JSONValue>, ...args: JSONValue[]) => JSONValue
}
 
/* Временно делаем функцию методом объекта */
Function.prototype.callPolyfill = function (context, ...args): JSONValue {
  let object = { ...context } as any
  let symbol = Symbol('context')
  // this здесь — это функция
  object[symbol] = this
  // Вызываем add как метод object
  return object[symbol](...args)
}
 
// Local check:
function add(this: { a: number }, b: number) {
  return this.a + b
}
 
console.log(add.callPolyfill({ a: 5 }, 7)) // 12
 
 
export {}

Example 1:
 
    Input:
    fn = function add(b) {
      return this.a + b;
    }
    args = [{ "a": 5 }, 7]
    Output: 12
    Explanation:
    fn.callPolyfill({ "a": 5 }, 7); // 12
    callPolyfill sets the "this" context to { "a": 5 }. 7 is passed as an
    argument.
 
  Example 2:
 
    Input:
    fn = function tax(price, taxRate) {
      return `The cost of the ${this.item} is ${price * taxRate}`;
    }
    args = [{ "item": "burger" }, 10, 1.1]
    Output: "The cost of the burger is 11"
    Explanation:
    callPolyfill sets the "this" context to { "item": "burger" }. 10 and 1.1
    are passed as additional arguments.

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