58 lines
4.9 KiB
Markdown
58 lines
4.9 KiB
Markdown
# Update `module` and `target` compiler options migration
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# 更新 `module` 和 `target` 编译器选项的迁移
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## What does this migration do?
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## 此迁移有什么作用？
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This migration adjusts the [`target`](https://www.typescriptlang.org/v2/en/tsconfig#target) and [`module`](https://www.typescriptlang.org/v2/en/tsconfig#module) settings within the [TypeScript configuration files](guide/typescript-configuration) for the workspace.
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The changes to each option vary based on the builder or command that uses the TypeScript configuration file.
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Unless otherwise noted, changes are only made if the existing value was not changed since the project was created.
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This process helps ensure that intentional changes to the options are kept in place.
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此迁移将调整工作区的 [TypeScript 配置文件](guide/typescript-configuration)中的 [`target`](https://www.typescriptlang.org/v2/en/tsconfig#target) 和 [`module`](https://www.typescriptlang.org/v2/en/tsconfig#module) 设置。对每个选项的更改根据使用 TypeScript 配置文件的构建器或命令而有所不同。除非另有说明，否则仅当自创建项目以来未更改过现有值的情况下才进行更改。此过程有助于确保对这些选项进行的更改都是符合意图的。
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| TypeScript Configuration File(s) | Changed Property | Existing Value | New Value |
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| -------------------------------- | ---------------- | -------------- | --------- |
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| TypeScript 配置文件 | 属性变更 | 现有值 | 新值 |
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| `<workspace base>/tsconfig.json` | `"module"` | `"esnext"` | `"es2020"` |
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| Used in `browser` builder options (`ng build` for applications) | `"module"` | `"esnext"` | `"es2020"` |
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| 在 `browser` 构建器选项中使用（用于应用程序的 `ng build`）| `"module"` | `"esnext"` | `"es2020"` |
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| Used in `ng-packgr` builder options (`ng build` for libraries) | `"module"` | `"esnext"` | `"es2020"` |
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| 在 `ng-packgr` 构建器选项中使用（用于库的 `ng build`）| `"module"` | `"esnext"` | `"es2020"` |
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| Used in `karma` builder options (`ng test` for applications) | `"module"` | `"esnext"` | `"es2020"` |
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| 在 `karma` 器选项中使用（用于应用程序的 `ng test`）| `"module"` | `"esnext"` | `"es2020"` |
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| Used in `server` builder options (universal) | `"module"` | `"commonjs"` | *removed* |
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| 在 `server` 构建器选项中使用（通用） | `"module"` | `"commonjs"` | *已移除* |
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| Used in `server` builder options (universal) | `"target"` | *any* | `"es2016"` |
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| 在 `server` 构建器选项中使用（通用） | `"target"` | *任何* | `"es2016"` |
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| Used in `protractor` builder options (`ng e2e` for applications) | `"target"` | `"es5"` | `"es2018"` |
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| 在 `protractor` 构建器选项中使用（用于应用程序的 `ng e2e`）| `"target"` | `"es5"` | `"es2018"` |
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## Why is this migration necessary?
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## 为什么需要此迁移？
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This migration provides improvements to the long-term supportability of projects by updating the projects to use recommended best practice compilation options.
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此迁移通过更新项目，让它使用建议的最佳实践编译选项，来改善项目的长期支持能力。
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For the functionality that executes on Node.js, such as Universal and Protractor, the new settings provide performance and troubleshooting benefits as well.
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The minimum Node.js version for the Angular CLI (v10.13) supports features in ES2018 and earlier.
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By targeting later ES versions, the compiler transforms less code and can use newer features directly.
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Since zone.js does not support native `async` and `await`, the universal builds still target ES2016.
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对于要在 Node.js 上执行的功能（例如 Universal 和 Protractor），新设置还提供了性能和故障排除方面的优势。Angular CLI 的最低 Node.js 版本（v10.13）支持 ES2018 及更早版本中的功能。通过瞄准更高版本的 ES，编译器可以转换更少的代码，并且可以直接使用新特性。由于 zone.js 不支持原生 `async` 和 `await` ，因此通用版本仍以 ES2016 为目标。
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## Why `"es2020"` instead of `"esnext"`?
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## 为什么用 `"es2020"` 代替 `"esnext"` ？
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In TypeScript 3.9, the behavior of the TypeScript compiler controlled by `module` is the same with both `"esnext"` and `"es2020"` values.
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This behavior can change in the future, because the `"esnext"` option could evolve in a backwards incompatible ways, resulting in build-time or run-time errors during a TypeScript update.
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As a result, code can become unstable. Using the `"es2020"` option mitigates this risk.
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在 TypeScript 3.9 中，由 `module` 控制的 TypeScript 编译器的行为与 `"esnext"` 和 `"es2020"` 值相同。此行为将来可能会更改，因为 `"esnext"` 选项可能会以向后不兼容的方式发展，从而导致在 TypeScript 更新时导致构建期或运行期错误。其后果是，代码可能变得不稳定。使用 `"es2020"` 选项可减轻此风险。
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