Function cssReplaceVarValue

scripts/themeable/custom-theme-webpack-loader.js:99–138

* * @param {*} css css文本内容 * @param {*} reg 匹配的正则 * @param {*} replaceFn 正则的替换函数 * @param {*} fallBackHandler 处理回落的正则和替换函数 * @param {} fallbackStrategy 策略

(css, reg, replaceFn, fallBackHandler = null, fallbackStrategy = 'enforce')

 * @param {} fallbackStrategy 策略
 */
function cssReplaceVarValue(css, reg, replaceFn, fallBackHandler = null, fallbackStrategy = 'enforce') {
  const replaceOriginValue = (reg,replaceFn,fallBackHandler,fallbackStrategy) => {
    return {
      postcssPlugin: 'postcss-plugin-replace-var-value',
      Once(root, { result }) {
        root.walkDecls(decl => {
          if (decl.type !== 'comment' && decl.value && decl.value.match(reg)) {
            var newDecl = decl.clone({ value: decl.value.replace(reg, replaceFn) });
            decl.replaceWith(newDecl);
            if (fallBackHandler) {
              var declPrev = newDecl.prev();
              var regFallback = fallBackHandler.reg;
              var replaceFnFallBack = fallBackHandler.replaceFn;
              if (declPrev && declPrev.type !== 'comment' && declPrev.value
                && declPrev.toString() === decl.clone({ value: decl.value.replace(regFallback, replaceFnFallBack) }).toString()) {
                if ('remove' === fallbackStrategy) {
                  declPrev.remove();
                } else {
                  declPrev.replaceWith(newDecl.clone({ value: newDecl.value.replace(regFallback, replaceFnFallBack) }));
                  if ('only' === fallbackStrategy) {
                    newDecl.remove();
                  }
                }

              } else {
                if ('enforce' === fallbackStrategy || true === fallbackStrategy || 'only' === fallbackStrategy) {
                  newDecl.cloneBefore({ value: newDecl.value.replace(regFallback, replaceFnFallBack) });
                  if ('only' === fallbackStrategy) {
                    newDecl.remove();
                  }
                }
              }
            }
          }
        });
      }
    }
  }
  return postcss([replaceOriginValue(reg,replaceFn,fallBackHandler,fallbackStrategy)]).process(css).css;
}

function process(source, map) {
  this.cacheable && this.cacheable();