react-native/Libraries/Inspector/resolveBoxStyle.js

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/**
* Copyright (c) Facebook, Inc. and its affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*
* @format
* @flow
*/
'use strict';
const I18nManager = require('I18nManager');
/**
* Resolve a style property into its component parts.
*
* For example:
*
* > resolveProperties('margin', {margin: 5, marginBottom: 10})
* {top: 5, left: 5, right: 5, bottom: 10}
*
* If no parts exist, this returns null.
*/
function resolveBoxStyle(
prefix: string,
style: Object,
): ?$ReadOnly<{|
bottom: number,
left: number,
right: number,
top: number,
|}> {
let hasParts = false;
const result = {
bottom: 0,
left: 0,
right: 0,
top: 0,
};
// TODO: Fix issues with multiple properties affecting the same side.
const styleForAll = style[prefix];
if (styleForAll != null) {
for (const key of Object.keys(result)) {
result[key] = styleForAll;
}
hasParts = true;
}
const styleForHorizontal = style[prefix + 'Horizontal'];
if (styleForHorizontal != null) {
result.left = styleForHorizontal;
result.right = styleForHorizontal;
hasParts = true;
} else {
const styleForLeft = style[prefix + 'Left'];
if (styleForLeft != null) {
result.left = styleForLeft;
hasParts = true;
}
const styleForRight = style[prefix + 'Right'];
if (styleForRight != null) {
result.right = styleForRight;
hasParts = true;
}
const styleForEnd = style[prefix + 'End'];
if (styleForEnd != null) {
if (I18nManager.isRTL && I18nManager.doLeftAndRightSwapInRTL) {
result.left = styleForEnd;
} else {
result.right = styleForEnd;
}
hasParts = true;
}
const styleForStart = style[prefix + 'Start'];
if (styleForStart != null) {
if (I18nManager.isRTL && I18nManager.doLeftAndRightSwapInRTL) {
result.right = styleForStart;
} else {
result.left = styleForStart;
}
hasParts = true;
}
}
const styleForVertical = style[prefix + 'Vertical'];
if (styleForVertical != null) {
result.bottom = styleForVertical;
result.top = styleForVertical;
hasParts = true;
} else {
const styleForBottom = style[prefix + 'Bottom'];
if (styleForBottom != null) {
result.bottom = styleForBottom;
hasParts = true;
}
const styleForTop = style[prefix + 'Top'];
if (styleForTop != null) {
result.top = styleForTop;
hasParts = true;
}
}
return hasParts ? result : null;
}
module.exports = resolveBoxStyle;