Angular Nx Tutorial - Step 10: Computation Caching

Nx has built-in computation caching, which helps drastically improve the performance of the commands.

To see it in action, run npx nx build todos:

❯ nx build todos > nx run todos:build:production ✔ Browser application bundle generation complete. ✔ Copying assets complete. ✔ Index html generation complete. Initial Chunk Files | Names | Raw Size | Estimated Transfer Size main.198853e72abe040f.js | main | 125.05 kB | 35.88 kB polyfills.80c46001d98dd563.js | polyfills | 36.21 kB | 11.49 kB runtime.db95d73b9ee480c5.js | runtime | 1.04 kB | 599 bytes styles.ef46db3751d8e999.css | styles | 0 bytes | - | Initial Total | 162.30 kB | 47.96 kB Build at: 2022-01-21T20:36:14.528Z - Hash: 795c96ce5e48a766 - Time: 11596ms ——————————————————————————————————————————————— > NX SUCCESS Running target "build" succeeded

Now, run npx nx build todos again, and you will see the results appearing instantly:

❯ nx build todos > nx run todos:build:production [existing outputs match the cache, left as is] Initial Chunk Files | Names | Raw Size | Estimated Transfer Size main.198853e72abe040f.js | main | 125.05 kB | 35.88 kB polyfills.80c46001d98dd563.js | polyfills | 36.21 kB | 11.49 kB runtime.db95d73b9ee480c5.js | runtime | 1.04 kB | 599 bytes styles.ef46db3751d8e999.css | styles | 0 bytes | - | Initial Total | 162.30 kB | 47.96 kB Build at: 2022-01-21T20:36:14.528Z - Hash: 795c96ce5e48a766 - Time: 11596ms ——————————————————————————————————————————————— > NX SUCCESS Running target "build" succeeded Nx read the output from cache instead of running the command for 1 out of 1 tasks.

Based on the state of the source code and the environment, Nx was able to figure out that it had already run this exact command. Nx found the artifact in the local cache and replayed the output and restored the necessary files.

Caching is a feature of Nx CLI

Caching only works with the Nx CLI. Running ng build todos runs the command every single time.

Building multiple projects

Use the run-many command to rebuild the two applications:

npx nx run-many --target=build --projects=todos,api

And notice the output:

Nx read the output from the cache instead of running the command for 1 out of 2 tasks.

Nx built api and retrieved todos from its computation cache. Read more about the cache here here.

Go faster

Add --parallel to any command, and Nx does most of the work in parallel.

What's Next