build: Speed up playground build

As discussed in PRQL#1836 (comment)

Taskfile.yml

@@ -290,11 +290,14 @@ tasks:
     cmds:
       - mdbook serve --port=3000
 
+  # Use `npm install --install-links=false` to install prql-js
+  # as the regular dependency, instead of creating a
+  # symlink. Refer to https://github.com/PRQL/prql/pull/1296.
   run-playground:
     desc: Build & serve the playground.
     dir: web/playground
     cmds:
-      - npm install --install-links=false
+      - npm install --install-links=false --profile=dev
       - npm start
 
   run-playground-cached:
@@ -309,13 +312,10 @@ tasks:
     # Use task's sources/generates to see if checksums of
     # node_modules directory have changed since package.json was updated
 
-    # Use `npm install --install-links=false` to install prql-js
-    # as the regular dependency, instead of creating a
-    # symlink. Refer to https://github.com/PRQL/prql/pull/1296.
     desc: Check to see if package.json has changed since we ran npm install
     dir: web/playground
     cmds:
-      - npm install --install-links=false
+      - npm install --install-links=false --profile=dev
     sources:
       - package.json
     generates:

bindings/prql-js/README.md

@@ -8,6 +8,14 @@ JavaScript bindings for [`prql-compiler`](https://github.com/PRQL/prql/).
 npm install prql-js
 ```
 
+Pass `--profile=dev` for a faster, less optimized build. Without this, the
+`wasm` binaries are optimized on each run, even if the underlying code hasn't
+changed.
+
+```sh
+npm install prql-js --profile=dev
+```
+
 ## Usage
 
 Currently these functions are exposed