reducePositions.js
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'use strict';
exports.__esModule = true;
var _extends = Object.assign || function (target) { for (var i = 1; i < arguments.length; i++) { var source = arguments[i]; for (var key in source) { if (Object.prototype.hasOwnProperty.call(source, key)) { target[key] = source[key]; } } } return target; };
var _postcss = require('postcss');
var _postcssValueParser = require('postcss-value-parser');
var _postcssValueParser2 = _interopRequireDefault(_postcssValueParser);
var _has = require('has');
var _has2 = _interopRequireDefault(_has);
var _getArguments = require('./getArguments');
var _getArguments2 = _interopRequireDefault(_getArguments);
function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
var directions = ['top', 'right', 'bottom', 'left', 'center'];
var properties = ['background', 'background-position', '-webkit-perspective-origin', 'perspective-origin'];
var center = '50%';
var horizontal = {
right: '100%',
left: '0'
};
var vertical = {
bottom: '100%',
top: '0'
};
function transform(decl) {
if (!~properties.indexOf(decl.prop)) {
return;
}
var values = (0, _postcssValueParser2.default)(decl.value);
var args = (0, _getArguments2.default)(values);
var relevant = [];
args.forEach(function (arg) {
relevant.push({
start: null,
end: null
});
arg.forEach(function (part, index) {
var isPosition = ~directions.indexOf(part.value) || (0, _postcssValueParser.unit)(part.value);
var 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(function (range, index) {
if (range.start === null) {
return;
}
var position = args[index].slice(range.start, range.end + 1);
if (position.length > 3) {
return;
}
if (position.length === 1 || position[2].value === 'center') {
if (position[2]) {
position[2].value = position[1].value = '';
}
var value = position[0].value;
var map = _extends({}, horizontal, {
center: center
});
if ((0, _has2.default)(map, value)) {
position[0].value = map[value];
}
return;
}
if (position[0].value === 'center' && ~directions.indexOf(position[2].value)) {
position[0].value = position[1].value = '';
var _value = position[2].value;
if ((0, _has2.default)(horizontal, _value)) {
position[2].value = horizontal[_value];
}
return;
}
if ((0, _has2.default)(horizontal, position[0].value) && (0, _has2.default)(vertical, position[2].value)) {
position[0].value = horizontal[position[0].value];
position[2].value = vertical[position[2].value];
return;
} else if ((0, _has2.default)(vertical, position[0].value) && (0, _has2.default)(horizontal, position[2].value)) {
var first = position[0].value;
position[0].value = horizontal[position[2].value];
position[2].value = vertical[first];
return;
}
});
decl.value = values.toString();
}
exports.default = (0, _postcss.plugin)('cssnano-reduce-positions', function () {
return function (css) {
return css.walkDecls(transform);
};
});
module.exports = exports['default'];