gulpparallel

Gulpparallel is a utility function in the Gulp JavaScript task runner that enables running multiple tasks concurrently. It is a core feature of Gulp 4 and is exposed by requiring the gulp module as parallel. Alongside gulp.series, it provides a way to compose tasks so that independent steps run at the same time.

Parallel accepts any number of task functions or named tasks and returns a function. When the returned function is invoked, it starts all input tasks at the same time and completes when all have signaled completion. Each task can signal completion by returning a stream, a promise, calling a callback, or emitting an end event. This makes it suitable for I/O bound work such as compiling styles, bundling scripts, or optimizing assets, when these steps do not depend on each other’s outputs.

Usage typically involves defining individual tasks and then exporting a combined task using parallel. For example, you might export a build task that runs CSS processing, JavaScript bundling, and image optimization in parallel. You would then invoke this build task via the Gulp CLI, for instance by running gulp build.

Notes and limitations: Parallel does not guarantee a specific execution order or data dependencies between tasks. If one task relies on the output of another, use series to enforce sequential execution. Excessive concurrency can increase resource usage or cause contention if tasks write to shared files. In practice, parallel is a function that composes independent tasks and executes them together when invoked.