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author | Michaël Zasso <targos@protonmail.com> | 2017-12-22 16:53:42 +0100 |
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committer | Michaël Zasso <targos@protonmail.com> | 2018-01-11 09:48:05 +0100 |
commit | 3dc30632755713179f345f4af024bd904c6162d0 (patch) | |
tree | f28c4f6dd6dfc5992edf301449d1a371d229755b /tools/node_modules/eslint/node_modules/file-entry-cache/README.md | |
parent | a2c7085dd4a8e60d1a47572aca8bb6fcb7a32f88 (diff) | |
download | android-node-v8-3dc30632755713179f345f4af024bd904c6162d0.tar.gz android-node-v8-3dc30632755713179f345f4af024bd904c6162d0.tar.bz2 android-node-v8-3dc30632755713179f345f4af024bd904c6162d0.zip |
tools: move eslint from tools to tools/node_modules
This is required because we need to add the babel-eslint dependency
and it has to be able to resolve "eslint".
babel-eslint is required to support future ES features such as async
iterators and import.meta.
Refs: https://github.com/nodejs/node/pull/17755
PR-URL: https://github.com/nodejs/node/pull/17820
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Diffstat (limited to 'tools/node_modules/eslint/node_modules/file-entry-cache/README.md')
-rw-r--r-- | tools/node_modules/eslint/node_modules/file-entry-cache/README.md | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/tools/node_modules/eslint/node_modules/file-entry-cache/README.md b/tools/node_modules/eslint/node_modules/file-entry-cache/README.md new file mode 100644 index 0000000000..19d25f0445 --- /dev/null +++ b/tools/node_modules/eslint/node_modules/file-entry-cache/README.md @@ -0,0 +1,107 @@ +# file-entry-cache +> Super simple cache for file metadata, useful for process that work o a given series of files +> and that only need to repeat the job on the changed ones since the previous run of the process — Edit + +[![NPM Version](http://img.shields.io/npm/v/file-entry-cache.svg?style=flat)](https://npmjs.org/package/file-entry-cache) +[![Build Status](http://img.shields.io/travis/royriojas/file-entry-cache.svg?style=flat)](https://travis-ci.org/royriojas/file-entry-cache) + +## install + +```bash +npm i --save file-entry-cache +``` + +## Usage + +```js +// loads the cache, if one does not exists for the given +// Id a new one will be prepared to be created +var fileEntryCache = require('file-entry-cache'); + +var cache = fileEntryCache.create('testCache'); + +var files = expand('../fixtures/*.txt'); + +// the first time this method is called, will return all the files +var oFiles = cache.getUpdatedFiles(files); + +// this will persist this to disk checking each file stats and +// updating the meta attributes `size` and `mtime`. +// custom fields could also be added to the meta object and will be persisted +// in order to retrieve them later +cache.reconcile(); + +// use this if you want the non visited file entries to be kept in the cache +// for more than one execution +// +// cache.reconcile( true /* noPrune */) + +// on a second run +var cache2 = fileEntryCache.create('testCache'); + +// will return now only the files that were modified or none +// if no files were modified previous to the execution of this function +var oFiles = cache.getUpdatedFiles(files); + +// if you want to prevent a file from being considered non modified +// something useful if a file failed some sort of validation +// you can then remove the entry from the cache doing +cache.removeEntry('path/to/file'); // path to file should be the same path of the file received on `getUpdatedFiles` +// that will effectively make the file to appear again as modified until the validation is passed. In that +// case you should not remove it from the cache + +// if you need all the files, so you can determine what to do with the changed ones +// you can call +var oFiles = cache.normalizeEntries(files); + +// oFiles will be an array of objects like the following +entry = { + key: 'some/name/file', the path to the file + changed: true, // if the file was changed since previous run + meta: { + size: 3242, // the size of the file + mtime: 231231231, // the modification time of the file + data: {} // some extra field stored for this file (useful to save the result of a transformation on the file + } +} + +``` + +## Motivation for this module + +I needed a super simple and dumb **in-memory cache** with optional disk persistence (write-back cache) in order to make +a script that will beautify files with `esformatter` to execute only on the files that were changed since the last run. + +In doing so the process of beautifying files was reduced from several seconds to a small fraction of a second. + +This module uses [flat-cache](https://www.npmjs.com/package/flat-cache) a super simple `key/value` cache storage with +optional file persistance. + +The main idea is to read the files when the task begins, apply the transforms required, and if the process succeed, +then store the new state of the files. The next time this module request for `getChangedFiles` will return only +the files that were modified. Making the process to end faster. + +This module could also be used by processes that modify the files applying a transform, in that case the result of the +transform could be stored in the `meta` field, of the entries. Anything added to the meta field will be persisted. +Those processes won't need to call `getChangedFiles` they will instead call `normalizeEntries` that will return the +entries with a `changed` field that can be used to determine if the file was changed or not. If it was not changed +the transformed stored data could be used instead of actually applying the transformation, saving time in case of only +a few files changed. + +In the worst case scenario all the files will be processed. In the best case scenario only a few of them will be processed. + +## Important notes +- The values set on the meta attribute of the entries should be `stringify-able` ones if possible, flat-cache uses `circular-json` to try to persist circular structures, but this should be considered experimental. The best results are always obtained with non circular values +- All the changes to the cache state are done to memory first and only persisted after reconcile. +- By default non visited entries are removed from the cache. This is done to prevent the file from growing too much. If this is not an issue and + you prefer to do a manual pruning of the cache files, you can pass `true` to the `reconcile` call. Like this: + + ```javascript + cache.reconcile( true /* noPrune */ ); + ``` + +## License + +MIT + + |