mirror of
https://github.com/facebook/react-native.git
synced 2025-11-01 09:14:26 +00:00
George Zahariev
d992ae0448
Summary:
Codemod `Object.assign` with object literal first argument (e.g. `Object.assign({}, foo)`) to object spread.
This adds several suppressions for exposed errors. The codemod produces errors as `Object.assign` is more unsafe than object spread. For example, `Object.assign` doesn't handle indexers, nor does it handle inexact objects properly, and when the (currently unsealed) empty object is supplied as the first argument, it also leads to unsafe behaviour:
https://flow.org/try/#0FAehAIGJwSQOwCYFMAeSBOBnYyDGAbAQ3SXADdjwBbQgBwC5wBvAbUwBd0BLOAcwF1GHbnwC+AbmDAAFAHkARgCskudgDpCmTF15xpTQowCMogDTU6ASkbyA9rfxJCcS+PBhwAfm8ymwcAGG4Eam-gFqETS0oaKu7hAAyrQkhAjgGOi2WOCa6Si0KuxICFIe0PCohKo5AGZF6HlV7DgqRCTklDyVqowGQpw8vOYRahJSCsqqGlo6en3gAEQAFlwL5vLGZuBdKE1xHjtN4Li2AK74abZkGVzI4AAG8vfgUvphOYzLq6EB4BvBP3CEUOqhi+0SyScaQyWUwOThqAKqmKpQg0AAqnBME5HGkalwsOwcuheDIJoVptpdPotvMTNZmDV7Iw4KcqPIMLE3B5vN4gA
The codemod is safe to do, despite some Flow errors, as `Object.assign` and object spread are equivalent at runtime, with the exception that `Object.assign` triggers setters on the target object. However the codemod [does not run](https://github.com/eslint/eslint/blob/938dbdd6c310784cc8a7329efaeb0e34321b9e1f/lib/rules/prefer-object-spread.js#L283-L285) if the first argument (object literal) has getters/setters, so we are fine.
```
ag -l 'Object.assign\(' | xargs ag -l 'flow' | xargs js1 lint --rule '{"prefer-object-spread":2}' --fix
```
Some manual fixes
```
arc f
```
Reviewed By: SamChou19815
Differential Revision: D36023786
fbshipit-source-id: b682562e670410acf4175ba59ab285c7bdcfe052
52 lines
1.2 KiB
JavaScript
52 lines
1.2 KiB
JavaScript
/**
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* Copyright (c) Meta Platforms, Inc. and affiliates.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*
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* @format
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* @flow
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*/
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'use strict';
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type truncateOptions = {
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breakOnWords: boolean,
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minDelta: number,
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elipsis: string,
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...
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};
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const defaultOptions = {
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breakOnWords: true,
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minDelta: 10, // Prevents truncating a tiny bit off the end
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elipsis: '...',
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};
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// maxChars (including ellipsis)
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const truncate = function (
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str: ?string,
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maxChars: number,
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options?: truncateOptions,
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): ?string {
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options = {...defaultOptions, ...options};
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if (
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str &&
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str.length &&
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str.length - options.minDelta + options.elipsis.length >= maxChars
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) {
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// If the slice is happening in the middle of a wide char, add one more char
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const extraChar =
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str.charCodeAt(maxChars - options.elipsis.length) > 255 ? 1 : 0;
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str = str.slice(0, maxChars - options.elipsis.length + 1 + extraChar);
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if (options.breakOnWords) {
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const ii = Math.max(str.lastIndexOf(' '), str.lastIndexOf('\n'));
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str = str.slice(0, ii);
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}
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str = str.trim() + options.elipsis;
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}
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return str;
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};
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module.exports = truncate;
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