Trim Left

Today we discuss Trim Left

String.prototype.trimStart does the same in JavaScript what we are about to do in TypeScript.

Let's try 👩‍💻

Iteration over a string

We already know how to iterate over:

• Object types (see Pick under the hood)
• Tuple types (see Making object out of tuple)
• Union types (see Exclude under the hood)

For strings we need several concepts:

1. Type inference in conditional types to infer substrings without whitespaces.
2. Template Literal types to match substrings in a string.

First, let's declare Whitespace which will be removed from the beginning:

Second, let's try to remove the first whitespace if it is a part of a string we pass. We will get something like this:

Not all test cases are completed because we don't remove whitespaces after the first one. Let's apply the type recursively:

That's it 💪

The solution is available in Playground

Have a good day and week 🌤