The Getting started with Heft tutorial introduced the
heft build and
heft test command-line actions. In this section, we’ll call out a few everyday commands that are particularly useful to know about. Refer to the Heft command line reference for a full listing of actions and parameters.
If you’re diagnosing problems with the Heft build, there are a couple useful parameters to be aware of:
--verbose: For example, instead of
heft build, you can run
heft build --verboseto see more details about how the tasks are invoked.
--debug: For even more detail, you can run
heft --debug buildto see call stacks and additional trace information. Note that
--debugis a global parameter, so it must precede the
Building with --watch
If you run
heft build --watch, the TypeScript compiler will continue running and wait for changes to source files. Whenever a file is changed, Heft will rebuild only the affected files, as a minimal incremental update that can be very fast.
When using Webpack,
heft start invokes a localhost dev server (see DevServer) that uses this mode to automatically reload the web browser with the recompiled code, every time a source file is saved. This can save a lot of time when tuning UI layouts! The
--watch parameter is not needed with
heft start, because watch mode is always enabled for that action.
Jest interactive shell
heft build, the
--watch parameter invokes Jest’s interactive shell, which shows a menu like this:
No tests found related to files changed since last commit. Press `a` to run all tests, or run Jest with `--watchAll`. Run start. 0 test suites Tests finished: Successes: 0 Failures: 0 Total: 0 Watch Usage › Press a to run all tests. › Press f to run only failed tests. › Press p to filter by a filename regex pattern. › Press t to filter by a test name regex pattern. › Press q to quit watch mode. › Press Enter to trigger a test run.
Whenever you save a change to a source file, Heft will automatically recompile, and then Jest will rerun any affected tests, updating the report.