Typescript has many ways to check if an element exists in an array. Now, let’s follow three ways to check if an array contains a value in typescript.
Check if an array contains a value in Typescript
Method 1: Includes() method
Syntax:
array.includes(value)
Parameter:
In Typescript(JS), includes() method determines whether the array includes an actual value among its entries, returning true or false.
For example:
// Create an array const arrayForChecking = [2, 4, 6]; let found = arrayForChecking.includes(4); if(found === true){ console.log("has contained in array"); } else { console.log("has not contained in array"); }
Console Output:
"has contained in array"
Include() method works a case-sensitive search to determine and find a string that exists in an array or not, returning true or false as appropriate. In the program, “4” exists at arrayForChecking[2]. Therefore include() will return true and the “If” function will return the True condition.
Method 2: Some() Method
Syntax:
array.some(function(value, index, arr), this)
Example:
const letter = ["a","b","c","d","e"]; const foundLetter = letter.some(letter => letter === 'b'); // true const foundAnotherLetter = letter.some(letter => letter === 'h'); // false if(foundLetter === true){ console.log("The letter has been found"); } else { console.log("The letter hasn't been found"); } if(foundAnotherLetter === true){ console.log("The letter has been found"); } else { console.log("The letter hasn't been found"); }
Console Output
The letter has been found // index.ts:7
The letter hasn't been found // index.ts:17
some() method checks all elements of an array if any element passes a condition and returns true if one of the arrays passes a condition and stops finding. Executes callback function once each array element. Returns false if the function returns false for all of the array elements.
Method 3: Find() Method
Similar to some() method, find() also checks all elements in the array BUT if one of the elements in array passes condition, find() method will return a Value not a boolean like some() method.
For instance:
const letter = ["a","b","c","d","e"]; const found = letter.find(letter => letter === 'b'); console.log(found);
Console Output:
"b"
Summary
To check if an array contains a value in typescript, I showed you three ways to check it. I hope you understand and make them in your project. If you want to know more methods about an array in TS/JS, this guide can show all methods you need. Thanks for reading.

Hello, my name is Philip Cabrera. My job is a programmer, and I have 4 years of programming expertise. Follow me if you need assistance with C, C++, JS, TS, or Node.js. I hope my posts are useful to you.
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