How to Efficiently Check for Substring Matches from an Array in JavaScript?

String Matching with Array Substrings in JavaScript

Problem: How to efficiently determine if a given string contains any substring from a predefined array in JavaScript?

Solution:

There are two approaches you can take for this task:

1. Array.some() Method:

The array.some() method allows you to check if at least one element in the array satisfies a given condition. You can utilize it as follows:

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

Or, with arrow functions and the includes() method:

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

2. Regular Expression:

While there's no built-in function specifically designed for this type of search, you can construct a regular expression to match the desired substrings and use the test() method on the string. However, this approach can be computationally expensive for large arrays and strings.

<code class="javascript">const regex = new RegExp(`( ${substrings.join(' | ')} )`, 'g');
if (regex.test(str)) {
  // There's at least one matching substring
}</code>

Example:

Consider the following array of substrings and two different strings:

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

let str1 = "this has one";
let str2 = "this doesn't have any";</code>

Using the array.some() approach:

<code class="javascript">if (substrings.some(v => str1.includes(v))) {
  console.log(`Match using "${str1}"`);
} else {
  console.log(`No match using "${str1}"`);
}</code>

Output:

Match using "this has one"

<code class="javascript">if (substrings.some(v => str2.includes(v))) {
  console.log(`Match using "${str2}"`);
} else {
  console.log(`No match using "${str2}"`);
}</code>

Output:

No match using "this doesn't have any"

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