依据原npm安装后的node_modules目录生成一份yarn.lock文件

yarn import

This command assists the migration of projects currently relying on npm-shrinkwrap.json, minimizing the differences between the lockfile and the existing dependency tree as best as it can.

动机

许多项目目前使用 npm shrinkwrap 或将 node_modules 签入它们的源代码控制，因为它们的依赖关系树很脆弱。 这些项目无法轻易迁移到 Yarn，因为 yarn install 可能产生有很大差异的逻辑依赖关系树。 不是所有树都可以用 Yarn 的 yarn.lock 表示， 并且部分有效的树会在安装后自动按重复剔除。 These nuances and others present a significant barrier to manual migration.

yarn import 旨在使用在 node_modules 内找到的版本根据普通的 require.resolve() 决议规则生成一个 yarn.lock 文件以缓解这一重大问题。 In cases where the Yarn resolution mechanism can’t satisfy the existing dependency tree identically, alerts will be made so that you may manually review the changes. The existing node_modules tree will be checked for validity beforehand, and the resultant lockfile should be yarn installable without any surprises (failed compatibility, unresolvable dependencies, auto-dedupes, etc.)

  1. $ yarn import
  1. yarn import vx.x.x
  2. success Folder in sync.
  3. warning Using version "2.2.4" of "lru-cache" instead of "2.7.3" for "ngstorage > grunt > minimatch"
  4. warning Using version "2.0.6" of "readable-stream" instead of "2.2.9" for "ngstorage > karma > chokidar > readdirp"
  5. [...]
  6. success Saved lockfile.
  7. ✨  Done in 11.96s.

原文: https://yarnpkg.com/zh-Hans/docs/cli/import