2693-call-function-with-custom-context.js

/**
 * 2693. Call Function with Custom Context
 * https://leetcode.com/problems/call-function-with-custom-context/
 * Difficulty: Medium
 *
 * 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).
 *
 * For example if you had the function:
 *
 * function tax(price, taxRate) {
 *   const totalCost = price * (1 + taxRate);
 *   console.log(`The cost of ${this.item} is ${totalCost}`);
 * }
 *
 * Calling this function like tax(10, 0.1) will log "The cost of undefined is 11". This is
 * because the this context was not defined.
 *
 * However, calling the function like tax.callPolyfill({item: "salad"}, 10, 0.1) will log "The
 * cost of salad is 11". The this context was appropriately set, and the function logged an
 * appropriate output.
 *
 * Please solve this without using the built-in Function.call method.
 */

/**
 * @param {Object} context
 * @param {Array} args
 * @return {null|boolean|number|string|Array|Object}
 */
Function.prototype.callPolyfill = function(context, ...args) {
  return this.bind(context)(...args);
}