Provyn Prep · JavaScript and TypeScript competency
Modules & platform APIs in the JavaScript and TypeScript assessment
Modules & platform APIs is one of the areas a Provyn JavaScript and TypeScript credential scores separately, so a recruiter can see it on its own rather than averaged into one number. This guide explains what it covers, how it is tested and what to practice.
What it covers
Working with the language's built-in data structures and platform APIs: destructuring, spread, Map and Set, JSON serialization and module structure.
Topics in the practice set for this area
- data structures
- syntax / destructuring
- syntax / spread
- JSON / serialization
How it is tested
In the timed assessment, questions in this area use these formats: multiple choice, put the steps in order, short answer, written scenario. Each attempt draws its own set of questions, and this area gets its own sub-score on the credential when the attempt includes enough questions from it. The assessment questions themselves are never published; the practice set below is written separately for study.
What to practice
- Use destructuring and spread to copy and update nested objects without mutating the original.
- Know what JSON.stringify drops or changes (undefined, functions, Dates) and why.
- Choose between an object, a Map and a Set for three small problems and justify each choice.
Try a practice question
From the free practice set (6 questions in this area). Answers and explanations are in the practice set.
- Which Array method returns a new array holding only the elements that pass a test, leaving the original array unchanged?
- Complete the destructuring that pulls `name` from `user`.
- `[1, 2, 3].reduce((a, b) => a + b, 0)` returns:
Practice before the real thing
Both are free and use practice questions only, never questions from the real assessment.
More JavaScript and TypeScript study guides
Last reviewed 2026-10-06.