How to Detect Substrings in a String Using JavaScript?

Detecting Substrings in a String Using JavaScript

When working with strings in JavaScript, a common task is to verify whether they contain text from a predefined set of substrings. While JavaScript doesn't offer a built-in solution, here are two approaches to tackle this challenge.

Array some Method

Leveraging the Array some() method (ES5), you can iterate through the array of substrings and check if any of them exist within the target string.

<code class="javascript">if (substrings.some(function(v) { return str.indexOf(v) >= 0; })) {
    // There's at least one
}</code>

For cleaner code, consider using arrow functions and the includes() method (ES2015 ):

<code class="javascript">if (substrings.some(v => str.includes(v))) {
    // There's at least one
}</code>

Regular Expression

Another option involves using a regular expression. While more complex, this approach allows you to search for multiple patterns simultaneously.

<code class="javascript">const re = new RegExp(substrings.join('|'));
if (re.test(str)) {
    // There's at least one match
}</code>

By joining the substrings into a regular expression string, you can test for their presence in the target string.

Example

<code class="javascript">const substrings = ["one", "two", "three"];
const str = "this has one";

// Expected match
if (substrings.some(v => str.includes(v))) {
    console.log("Match found.");
} else {
    console.log("No match found.");
}</code>

Output:

Match found.

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