how to use the istypedarray function from the underscore library in typescript

To use the isTypedArray function from the Underscore library in TypeScript, you first need to import the Underscore library in your TypeScript file. You can do this using the import statement:

index.ts
import * as _ from 'underscore';
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Once you have imported the library, you can use the isTypedArray function to check if a variable is a typed array. The isTypedArray function takes one argument, which is the variable you want to test.

index.ts
const myArray: number[] = [1, 2, 3];
const myTypedArray: Float32Array = new Float32Array([1.0, 2.0, 3.0]);

console.log(_.isTypedArray(myArray)); // false
console.log(_.isTypedArray(myTypedArray)); // true
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Note that TypeScript is a strongly-typed language and the isTypedArray function does not have any type information. Therefore, you may need to use type assertion to ensure that the variable you are testing is of the correct type:

index.ts
const myArray: any = [1, 2, 3];
const myTypedArray: any = new Float32Array([1.0, 2.0, 3.0]);

console.log(_.isTypedArray(myArray as Float32Array)); // false
console.log(_.isTypedArray(myTypedArray as Float32Array)); // true
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In the example above, we use the as keyword to do a type assertion to cast the variables myArray and myTypedArray to the Float32Array type. This ensures that the isTypedArray function returns the correct value.