React 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:

> npx nx run todos:build

Starting type checking service...
Using 14 workers with 2048MB memory limit
Hash: c38fbdb8b372af447180
Built at: 03/26/2020 11:03:57 AM
Entrypoint main = runtime.ff0534391bf88384547e.js main.b8dbcd3d3fd2900377f2.esm.js
Entrypoint polyfills = runtime.ff0534391bf88384547e.js polyfills.55535a35b1529d884ca3.esm.js
Entrypoint styles = runtime.ff0534391bf88384547e.js styles.3ff695c00d717f2d2a11.css
chunk    {0} runtime.ff0534391bf88384547e.js (runtime) 0 bytes ={1}= ={2}= ={3}= [entry] [rendered]
chunk    {1} main.b8dbcd3d3fd2900377f2.esm.js (main) 155 KiB ={0}= [initial] [rendered]
chunk    {2} polyfills.55535a35b1529d884ca3.esm.js (polyfills) 239 KiB ={0}= [initial] [rendered]
chunk    {3} styles.3ff695c00d717f2d2a11.css (styles) 147 bytes ={0}= [initial] [rendered]

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

> npx nx run todos:build

>  NX   NOTE  Cached Output:

Starting type checking service...
Using 14 workers with 2048MB memory limit
Hash: c38fbdb8b372af447180
Built at: 03/26/2020 11:05:06 AM
Entrypoint main = runtime.ff0534391bf88384547e.js main.b8dbcd3d3fd2900377f2.esm.js
Entrypoint polyfills = runtime.ff0534391bf88384547e.js polyfills.55535a35b1529d884ca3.esm.js
Entrypoint styles = runtime.ff0534391bf88384547e.js styles.3ff695c00d717f2d2a11.css
chunk    {0} runtime.ff0534391bf88384547e.js (runtime) 0 bytes ={1}= ={2}= ={3}= [entry] [rendered]
chunk    {1} main.b8dbcd3d3fd2900377f2.esm.js (main) 155 KiB ={0}= [initial] [rendered]
chunk    {2} polyfills.55535a35b1529d884ca3.esm.js (polyfills) 239 KiB ={0}= [initial] [rendered]
chunk    {3} styles.3ff695c00d717f2d2a11.css (styles) 147 bytes ={0}= [initial] [rendered]

Based on the state of the source code and the environment, Nx figured 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.

Building multiple projects

Now, run npx nx run-many --target=build --projects=todos,api to rebuild the two applications:

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

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

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