Provyn Prep · JavaScript and TypeScript competency
Runtime semantics in the JavaScript and TypeScript assessment
Runtime semantics 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
How JavaScript actually evaluates code: type coercion, equality, scope and closures, `this` binding, operators and floating-point arithmetic.
Topics in the practice set for this area
- type coercion
- numeric precision
- scoping
- this / context
- closures
- operators
- runtime behavior
How it is tested
In the timed assessment, questions in this area use these formats: code you write, matching, multiple choice, short answer. 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
- Predict the output of short snippets that mix == and ===, then run them.
- Explain how a closure captures a loop variable with var versus let.
- Call the same function as a method, a plain function and an arrow function and note what `this` is each time.
Try a practice question
From the free practice set (8 questions in this area). Answers and explanations are in the practice set.
- What does `typeof null` return?
- What is `0.1 + 0.2 === 0.3` in JavaScript?
- Which keyword creates a block-scoped variable you cannot reassign?
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.