angular-docs-cn/integration/side-effects/snapshots/core
JoostK 3c6edcdf93 fix(core): do not error when `ngDevMode` is undeclared (#39415)
In production mode, the `ngDevMode` global may not have been declared.
This is typically not a problem, as optimizers should have removed all
usages of the `ngDevMode` variables. This does however require the
bundler/optimizer to have been configured in a certain way, as to allow
for `ngDevMode` guarded code to be removed.

As an example, Terser can be configured to remove the `ngDevMode`
guarded code using the following configuration:

```js
const terserOptions = {
  // ...
  compress: {
    // ...
    global_defs: require('@angular/compiler-cli').GLOBAL_DEFS_FOR_TERSER,
  }
}
```

(Taken from https://github.com/angular/angular/issues/31595#issuecomment-519129090)

If this is not done, however, the bundle should still work (albeit with
larger code size due to missed tree-shaking opportunities). This commit
adds a check for whether `ngDevMode` has been declared, as it is a
top-level statement that executes before `ngDevMode` has been initialized.

Fixes #31595

PR Close #39415
2020-10-27 10:45:18 -07:00
..
esm2015.js fix(core): do not error when `ngDevMode` is undeclared (#39415) 2020-10-27 10:45:18 -07:00