index.js
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'use strict';
Object.defineProperty(exports, "__esModule", {
value: true
});
var _postcss = require('postcss');
var _postcssValueParser = require('postcss-value-parser');
var _postcssValueParser2 = _interopRequireDefault(_postcssValueParser);
var _cssnanoUtilGetArguments = require('cssnano-util-get-arguments');
var _cssnanoUtilGetArguments2 = _interopRequireDefault(_cssnanoUtilGetArguments);
var _has = require('has');
var _has2 = _interopRequireDefault(_has);
function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
const directions = ['top', 'right', 'bottom', 'left', 'center'];
const center = '50%';
const horizontal = {
right: '100%',
left: '0'
};
const vertical = {
bottom: '100%',
top: '0'
};
function transform(value) {
const parsed = (0, _postcssValueParser2.default)(value);
const args = (0, _cssnanoUtilGetArguments2.default)(parsed);
const relevant = [];
args.forEach(arg => {
relevant.push({
start: null,
end: null
});
arg.forEach((part, index) => {
const isPosition = ~directions.indexOf(part.value.toLowerCase()) || (0, _postcssValueParser.unit)(part.value);
const len = relevant.length - 1;
if (relevant[len].start === null && isPosition) {
relevant[len].start = index;
relevant[len].end = index;
return;
}
if (relevant[len].start !== null) {
if (part.type === 'space') {
return;
} else if (isPosition) {
relevant[len].end = index;
return;
}
return;
}
});
});
relevant.forEach((range, index) => {
if (range.start === null) {
return;
}
const position = args[index].slice(range.start, range.end + 1);
if (position.length > 3) {
return;
}
const firstValue = position[0].value.toLowerCase();
const secondValue = position[2] && position[2].value ? position[2].value.toLowerCase() : null;
if (position.length === 1 || secondValue === 'center') {
if (secondValue) {
position[2].value = position[1].value = '';
}
const map = Object.assign({}, horizontal, {
center
});
if ((0, _has2.default)(map, firstValue)) {
position[0].value = map[firstValue];
}
return;
}
if (firstValue === 'center' && ~directions.indexOf(secondValue)) {
position[0].value = position[1].value = '';
if ((0, _has2.default)(horizontal, secondValue)) {
position[2].value = horizontal[secondValue];
}
return;
}
if ((0, _has2.default)(horizontal, firstValue) && (0, _has2.default)(vertical, secondValue)) {
position[0].value = horizontal[firstValue];
position[2].value = vertical[secondValue];
return;
} else if ((0, _has2.default)(vertical, firstValue) && (0, _has2.default)(horizontal, secondValue)) {
position[0].value = horizontal[secondValue];
position[2].value = vertical[firstValue];
return;
}
});
return parsed.toString();
}
exports.default = (0, _postcss.plugin)('postcss-normalize-positions', () => {
return css => {
const cache = {};
css.walkDecls(/^(background(-position)?|(-webkit-)?perspective-origin)$/i, decl => {
const value = decl.value;
if (cache[value]) {
decl.value = cache[value];
return;
}
const result = transform(value);
decl.value = result;
cache[value] = result;
});
};
});
module.exports = exports['default'];