How to use Array.prototype.join() with Array.from() In Javascript

The Array.from() method creates a new, shallow-copied Array instance from an array-like or iterable object. By converting the string into an array of characters, we can easily manipulate and then join the desired portion back into a string.

Example: This example demonstrates using Array.from() to convert the string to an array of characters, then slicing and joining them to keep only the first n characters.

JavaScript
// JavaScript to keep only first 'n' characters of String

// Original string
let str = "OpenAI GPT-4";

// Keep first 8 characters
let n = 8;

console.log("Original String = " + str);
console.log("n = " + n);

// Using Array.from() and join() method
str = Array.from(str).slice(0, n).join('');

console.log("Keep first " + n + " characters of original String = " + str);

Output
Original String = OpenAI GPT-4
n = 8
Keep first 8 characters of original String = OpenAI G




JavaScript to keep only first N characters in a string

In this article, we have given a string and the task is to keep only the first n characters of the string using JavaScript. There are various methods to solve this problem, some of which are discussed below: 

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Methods to keep only First N characters in a String:

Table of Content Using substring() MethodUsing slice() MethodUsing JavaScript For loopUsing String’s substr() Method...

Method 1: Using substring() Method

The string.substring() method is used to return the part of the given string from the start index to the end index. Indexing starts from zero (0)....

Method 2: Using slice() Method

The string.slice() method is used to return a part or slice of the given input string....

Method 3: Using JavaScript For loop

Looping in programming languages is a feature that facilitates the execution of a set of instructions repeatedly until some condition evaluates and becomes false. We come across for loop which provides a brief and systematic way of writing the loop structure....

Method 4: Using String’s substr() Method

The substr() method is used to extract parts of a string, beginning at the specified start position, and returns the specified number of characters....

Method 5: Using Array.prototype.join() with Array.from()

The Array.from() method creates a new, shallow-copied Array instance from an array-like or iterable object. By converting the string into an array of characters, we can easily manipulate and then join the desired portion back into a string....