Polyfills are essential tools for developers aiming to create web applications compatible with a wide range of browsers. These code snippets bridge the gap between modern functionalities and older browser limitations.
Today, we'll delve into the apply() function and explore how to implement a polyfill for it, ensuring your applications function seamlessly across different browser environments.
Given below is a line by line explanation of the code.
The apply() method in JS invokes a function with a specified "this" value and allows passing arguments in an array.
Ln:1, person is an object.
Ln:5, printAge is a function, that takes age as an arg. (Apply method can take N number of arguments in the array).
Ln:9, Function.prototype.myApply is our polyfill that handles the apply method. It takes the object and [arguments].
Ln:11, we check whether the typeOf "this" and typeOf the ...args, if both satisfies then,
Ln:10, we make a key in the object naming it fn and assigning "this" to it. "this" refers to the printAge function() here.
Ln:19 we call the function with the arguments.
Ln:22, we call the myApply method here and get to see our output in the console.
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