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How to check if an element exists in an array in TypeScript
Theodore Kelechukwu OnyejiakuOverview
TypeScript is a superset of JavaScript. With TypeScript, we can add more syntax, catch more errors and do a lot more. TypeScript runs anywhere JavasScript runs.
In this shot, we will check if an array in TypeScript contains an element by using the includes() method. This method returns a boolean value indicating if an element is present in the array.
Syntax
array.includes(element)
Syntax for includes() method
Parameters
element: This is the element we want to check if it is present in the given array.
Return value
If the element is present in the array, then true is returned. Otherwise, false is returned.
Code example
Let's see how this works in the following code:
// create arrays in TypeScript
let names: string[] = ["Theodore", "James", "Peter", "Amaka"]
let numbers : Array<number>;
numbers = [12, 34, 5, 0.9]
let cars : Array<string> = ["Porsche", "Toyota", "Lexus"]
// check if the arrays contain some elements
console.log(names.includes("Jude"))
console.log(names.includes("Theodore"))
console.log(numbers.includes(3))
console.log(numbers.includes(0.9))
console.log(cars.includes("Bugatti"))
console.log(cars.includes("Toyota"))Using includes() method on arrays
Explanation
- Lines 2–5: We create some arrays.
- Lines 8–13: Using the
includes()method, we check to see if some elements are present in the arrays. Then we print the results to the console.
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