在用react做一個h5的項目，遇到了一個坑，我在componentDidMount里面獲取不到正確的list元素高度，必須用到setTimeout才行，但是定時器也不靠譜啊， 有沒有更好的解決辦法呢webpack.config.js配置文件{          test: /\.(js|mjs)$/,          exclude: /@babel(?:\/|\\{1,2})runtime/,          loader: require.resolve('babel-loader'),          options: {            babelrc: false,            configFile: false,            compact: false,            presets: [              [                require.resolve('babel-preset-react-app/dependencies'),                { helpers: true },              ],            ],            cacheDirectory: true,            cacheCompression: isEnvProduction,                        // If an error happens in a package, it's possible to be            // because it was compiled. Thus, we don't want the browser            // debugger to show the original code. Instead, the code            // being evaluated would be much more helpful.            sourceMaps: false,          },        },        // "postcss" loader applies autoprefixer to our CSS.        // "css" loader resolves paths in CSS and adds assets as dependencies.        // "style" loader turns CSS into JS modules that inject <style> tags.        // In production, we use MiniCSSExtractPlugin to extract that CSS        // to a file, but in development "style" loader enables hot editing        // of CSS.        // By default we support CSS Modules with the extension .module.css        {          test: cssRegex,          exclude: cssModuleRegex,          use: getStyleLoaders({            importLoaders: 1,            sourceMap: isEnvProduction && shouldUseSourceMap,          }),          // Don't consider CSS imports dead code even if the          // containing package claims to have no side effects.          // Remove this when webpack adds a warning or an error for this.          // See https://github.com/webpack/webpack/issues/6571          sideEffects: true,        },