How to make filter and word replacement method - JavaScript?

In JavaScript, there's no built-in method to replace all occurrences of a word in a string. You can create custom functions using methods like split() and join(), or use modern approaches like replaceAll().

Let's explore different methods to filter and replace words in a string:

var sentence = "Yes, My Name is John Smith. I live in US. Yes, My Favourite Subject is JavaScript";

Method 1: Using split() and join()

This method splits the string by the target word and joins the parts with the replacement:

var sentence = "Yes, My Name is John Smith. I live in US. Yes, My Favourite Subject is JavaScript";
console.log("Original:", sentence);

function replaceWordWithSplitJoin(word, sentence, replaceValue) {
    return sentence.split(word).join(replaceValue);
}

var result = replaceWordWithSplitJoin("Yes", sentence, "Hi");
console.log("Modified:", result);

Original: Yes, My Name is John Smith. I live in US. Yes, My Favourite Subject is JavaScript
Modified: Hi, My Name is John Smith. I live in US. Hi, My Favourite Subject is JavaScript

Method 2: Using Regular Expression with replace()

Regular expressions provide more control over word matching and replacement:

var sentence = "Yes, My Name is John Smith. I live in US. Yes, My Favourite Subject is JavaScript";

function replaceWordWithRegex(word, sentence, replaceValue) {
    var regex = new RegExp(word, 'g'); // 'g' for global replacement
    return sentence.replace(regex, replaceValue);
}

var result = replaceWordWithRegex("Yes", sentence, "Hello");
console.log("With Regex:", result);

With Regex: Hello, My Name is John Smith. I live in US. Hello, My Favourite Subject is JavaScript

Method 3: Using replaceAll() (ES2021)

Modern JavaScript provides the replaceAll() method for simpler word replacement:

var sentence = "Yes, My Name is John Smith. I live in US. Yes, My Favourite Subject is JavaScript";

function replaceWordModern(word, sentence, replaceValue) {
    return sentence.replaceAll(word, replaceValue);
}

var result = replaceWordModern("Yes", sentence, "Absolutely");
console.log("With replaceAll:", result);

With replaceAll: Absolutely, My Name is John Smith. I live in US. Absolutely, My Favourite Subject is JavaScript

Advanced Filter and Replace Function

Here's a more comprehensive function that can filter and replace multiple words:

function filterAndReplace(sentence, replacements) {
    let result = sentence;
    
    for (let word in replacements) {
        result = result.split(word).join(replacements[word]);
    }
    
    return result;
}

var sentence = "Yes, My Name is John Smith. I live in US. Yes, My Favourite Subject is JavaScript";
var replacements = {
    "Yes": "Certainly",
    "John Smith": "Jane Doe", 
    "US": "Canada"
};

var result = filterAndReplace(sentence, replacements);
console.log("Multiple replacements:", result);

Multiple replacements: Certainly, My Name is Jane Doe. I live in Canada. Certainly, My Favourite Subject is JavaScript

Comparison

Conclusion

For simple word replacement, use split() and join() or replaceAll(). For complex patterns and case-insensitive matching, regular expressions provide the most flexibility and control.