searchString

A string to be searched for withinstr. Cannotbe a regex. All values that are not regexes arecoerced to strings, so omitting it or passingundefined causesincludes() to search for the string"undefined", which is rarely what you want.

positionOptional

The position within the string at which to begin searching forsearchString. (Defaults to0.)

true if the search string is found anywhere within the given string, including whensearchString is an empty string; otherwise,false.

TypeError

Thrown ifsearchStringis a regex.

This method lets you determine whether or not a string includes another string.

Theincludes() method is case sensitive. For example, the following expression returnsfalse:

"Blue Whale".includes("blue"); // returns false

You can work around this constraint by transforming both the original string and the search string to all lowercase:

"Blue Whale".toLowerCase().includes("blue"); // returns true

• Polyfill ofString.prototype.includes incore-js
• es-shims polyfill ofString.prototype.includes
• Array.prototype.includes()
• TypedArray.prototype.includes()
• String.prototype.indexOf()
• String.prototype.lastIndexOf()
• String.prototype.startsWith()
• String.prototype.endsWith()