TS code :
function myFunction(value:number) {
console.log(value);
}
JS code, post-compilation:
function myFunction(value) {
console.log(value);
}
Are there methods to uphold type safety even after the conversion from TypeScript to JavaScript?
Once your code is compiled to JavaScript, all type information is lost as JavaScript does not support static types. Typescript serves as a static type checker, ensuring type safety during development, but ultimately compiles down to plain JavaScript without any type annotations.
By writing your application in TypeScript, you can guarantee type safety during development and catch errors before runtime. However, it's important to note that even in TypeScript, using any and type assertions can bypass the type checking mechanism and introduce unsafe behavior.
JavaScript is known for its dynamic typing nature, where types are converted as needed through type coercion.
To ensure a specific type is used in your function, you must validate it within your code.
For instance:
function myFunction(value) {
if (typeof value !== "string") {
throw new Error("not a string");
}
console.log(value);
}
Note that this example demonstrates the concept only.
Even when passing a var x = new String("hello") to the function, an error will be thrown since the typeof x is object.
Therefore, extra caution should be taken during such checks.
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