JavaScript Runtime

Noun · Development

Definitions

  1. The full execution environment that runs JavaScript, consisting of an engine plus host-provided APIs, event loop behavior, module loading, timers, and I/O facilities. Browsers, Node.js, Deno, and Bun are all JavaScript runtimes, but they expose different capabilities around the same language.

    In plain English: It is the surrounding system that runs JavaScript and gives it useful features like timers, networking, or filesystem access.

    Example: "The code is valid JavaScript, but it needs a runtime with fetch and file APIs, so it won't behave the same in every environment."

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