0.2.0 - Mid migration

web/node_modules/postcss-merge-rules/dist/lib/ensureCompatibility.js

@@ -0,0 +1,155 @@
+'use strict';
+
+Object.defineProperty(exports, "__esModule", {
+    value: true
+});
+exports.pseudoElements = undefined;
+exports.default = ensureCompatibility;
+
+var _caniuseApi = require('caniuse-api');
+
+var _postcssSelectorParser = require('postcss-selector-parser');
+
+var _postcssSelectorParser2 = _interopRequireDefault(_postcssSelectorParser);
+
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
+
+const simpleSelectorRe = /^#?[-._a-z0-9 ]+$/i;
+
+const cssSel2 = 'css-sel2';
+const cssSel3 = 'css-sel3';
+const cssGencontent = 'css-gencontent';
+const cssFirstLetter = 'css-first-letter';
+const cssFirstLine = 'css-first-line';
+const cssInOutOfRange = 'css-in-out-of-range';
+
+const pseudoElements = exports.pseudoElements = {
+    ':active': cssSel2,
+    ':after': cssGencontent,
+    ':before': cssGencontent,
+    ':checked': cssSel3,
+    ':default': 'css-default-pseudo',
+    ':dir': 'css-dir-pseudo',
+    ':disabled': cssSel3,
+    ':empty': cssSel3,
+    ':enabled': cssSel3,
+    ':first-child': cssSel2,
+    ':first-letter': cssFirstLetter,
+    ':first-line': cssFirstLine,
+    ':first-of-type': cssSel3,
+    ':focus': cssSel2,
+    ':focus-within': 'css-focus-within',
+    ':has': 'css-has',
+    ':hover': cssSel2,
+    ':in-range': cssInOutOfRange,
+    ':indeterminate': 'css-indeterminate-pseudo',
+    ':lang': cssSel2,
+    ':last-child': cssSel3,
+    ':last-of-type': cssSel3,
+    ':matches': 'css-matches-pseudo',
+    ':not': cssSel3,
+    ':nth-child': cssSel3,
+    ':nth-last-child': cssSel3,
+    ':nth-last-of-type': cssSel3,
+    ':nth-of-type': cssSel3,
+    ':only-child': cssSel3,
+    ':only-of-type': cssSel3,
+    ':optional': 'css-optional-pseudo',
+    ':out-of-range': cssInOutOfRange,
+    ':placeholder-shown': 'css-placeholder-shown',
+    ':root': cssSel3,
+    ':target': cssSel3,
+    '::after': cssGencontent,
+    '::backdrop': 'dialog',
+    '::before': cssGencontent,
+    '::first-letter': cssFirstLetter,
+    '::first-line': cssFirstLine,
+    '::marker': 'css-marker-pseudo',
+    '::placeholder': 'css-placeholder',
+    '::selection': 'css-selection'
+};
+
+function isCssMixin(selector) {
+    return selector[selector.length - 1] === ':';
+}
+
+const isSupportedCache = {};
+
+// Move to util in future
+function isSupportedCached(feature, browsers) {
+    const key = JSON.stringify({ feature, browsers });
+    let result = isSupportedCache[key];
+
+    if (!result) {
+        result = (0, _caniuseApi.isSupported)(feature, browsers);
+        isSupportedCache[key] = result;
+    }
+
+    return result;
+}
+
+function ensureCompatibility(selectors, browsers, compatibilityCache) {
+    // Should not merge mixins
+    if (selectors.some(isCssMixin)) {
+        return false;
+    }
+    return selectors.every(selector => {
+        if (simpleSelectorRe.test(selector)) {
+            return true;
+        }
+        if (compatibilityCache && selector in compatibilityCache) {
+            return compatibilityCache[selector];
+        }
+        let compatible = true;
+        (0, _postcssSelectorParser2.default)(ast => {
+            ast.walk(node => {
+                const { type, value } = node;
+                if (type === 'pseudo') {
+                    const entry = pseudoElements[value];
+                    if (entry && compatible) {
+                        compatible = isSupportedCached(entry, browsers);
+                    }
+                }
+                if (type === 'combinator') {
+                    if (~value.indexOf('~')) {
+                        compatible = isSupportedCached(cssSel3, browsers);
+                    }
+                    if (~value.indexOf('>') || ~value.indexOf('+')) {
+                        compatible = isSupportedCached(cssSel2, browsers);
+                    }
+                }
+                if (type === 'attribute' && node.attribute) {
+                    // [foo]
+                    if (!node.operator) {
+                        compatible = isSupportedCached(cssSel2, browsers);
+                    }
+
+                    if (value) {
+                        // [foo="bar"], [foo~="bar"], [foo|="bar"]
+                        if (~['=', '~=', '|='].indexOf(node.operator)) {
+                            compatible = isSupportedCached(cssSel2, browsers);
+                        }
+                        // [foo^="bar"], [foo$="bar"], [foo*="bar"]
+                        if (~['^=', '$=', '*='].indexOf(node.operator)) {
+                            compatible = isSupportedCached(cssSel3, browsers);
+                        }
+                    }
+
+                    // [foo="bar" i]
+                    if (node.insensitive) {
+                        compatible = isSupportedCached('css-case-insensitive', browsers);
+                    }
+                }
+                if (!compatible) {
+                    // If this node was not compatible,
+                    // break out early from walking the rest
+                    return false;
+                }
+            });
+        }).processSync(selector);
+        if (compatibilityCache) {
+            compatibilityCache[selector] = compatible;
+        }
+        return compatible;
+    });
+}