Create 06. Call.md

Author: ps0305

Machine Coding/06. Call.md

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+```js
+/**
+ * Implements a custom version of Function.prototype.call
+ *
+ * @param {Object} thisArg - The value to use as `this` inside the function.
+ * @param {...any} argArray - Arguments to pass to the function.
+ */
+Function.prototype.myCall = function (thisArg, ...argArray) {
+  if (typeof this !== 'function') {
+    throw new TypeError('myCall must be called on a function');
+  }
+
+  // Ensuring `thisArg` is an object (or `null`/`undefined`)
+  thisArg = thisArg !== undefined && thisArg !== null ? Object(thisArg) : globalThis;
+
+  // Assign the function to a temporary property on `thisArg`
+  const uniqueSymbol = Symbol('tempFunction'); // Ensures no collisions with existing properties
+  thisArg[uniqueSymbol] = this;
+
+  // Invoke the function using the provided arguments
+  const result = thisArg[uniqueSymbol](...argArray);
+
+  // Clean up: Remove the temporary property from `thisArg`
+  delete thisArg[uniqueSymbol];
+
+  return result; // Return the result of the function call
+};
+```
+
+### Explanation
+#### Ensure Valid Input:
+
+* If this (the function being called) is not a function, throw a TypeError.
+* This ensures that myCall is only called on valid function objects.
+#### Handle thisArg:
+
+Convert thisArg into an object, unless it’s null or undefined. If thisArg is null or undefined, default to the global object (globalThis in modern JavaScript environments).
+#### Assign Function to Temporary Property:
+
+* Create a unique property with a Symbol (to avoid property name collisions).
+* Temporarily assign the function being invoked (this) to this property on thisArg.
+#### Invoke the Function:
+
+Use the temporary property to call the function with the correct this context and pass in the arguments (...argArray).
+#### Clean Up:
+
+Delete the temporary property after invoking the function to avoid modifying the original object permanently.
+#### Return the Result:
+
+Return the value produced by the invocation of the function.
+
+### Edge Cases
+* `Null` or `Undefined` thisArg: If thisArg is null or undefined, the global object (globalThis) is used as the context.
+
+* Primitive Values for `thisArg`: Primitive values (e.g., 42, "hello", true) are automatically boxed into their respective object wrappers (Number, String, Boolean).