Sebastian Markbage 433fb336af Refactor Attribute Processing (Step 4)
Summary:This avoids flattening styles in most common cases. It diffs against the nested
arrays. The special case is when a property gets removed, it creates an object
that stores the removed keys which then gets resolved using a second pass
through the nested array.

You can conceptually think of this algorithm as:
1) Diff and store changes as you go
2) If something was removed, flatten as necessary

I also merged in another commit that renames the StyleSheetRegistry to ReactNativePropRegistry. There is nothing in here that makes it specific to styles anymore. That's just a decoupled view attribute configuration option. This registry can be used for any set of nested props, if we even want to keep this feature at all.

Reviewed By: vjeux

Differential Revision: D2492885

fb-gh-sync-id: c976ac28b7e63545132c36da0ee0c1c562e7c9e5
shipit-source-id: c976ac28b7e63545132c36da0ee0c1c562e7c9e5
2016-03-24 15:13:24 -07:00

49 lines
1.1 KiB
JavaScript

/**
* Copyright (c) 2015-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*
* @providesModule flattenStyle
* @flow
*/
'use strict';
var ReactNativePropRegistry = require('ReactNativePropRegistry');
var invariant = require('fbjs/lib/invariant');
import type { StyleObj } from 'StyleSheetTypes';
function getStyle(style) {
if (typeof style === 'number') {
return ReactNativePropRegistry.getByID(style);
}
return style;
}
function flattenStyle(style: ?StyleObj): ?Object {
if (!style) {
return undefined;
}
invariant(style !== true, 'style may be false but not true');
if (!Array.isArray(style)) {
return getStyle(style);
}
var result = {};
for (var i = 0; i < style.length; ++i) {
var computedStyle = flattenStyle(style[i]);
if (computedStyle) {
for (var key in computedStyle) {
result[key] = computedStyle[key];
}
}
}
return result;
}
module.exports = flattenStyle;