做了一个小测试。渲染了 100 个组件，每个组件有 10 个嵌套布局。有和没有 flexbox。以下是代码片段：

组件/index.js

@CSSModules(styles, { allowMultiple: true })
export default class TheComponent extends Component {
  render() {
    const { deepNest, flex } = this.props

    return (
      <div>{ this.renderComp(deepNest, flex) }</div>
    )
  }

  renderComp(deepNest, flex) {
    const flexProperties = [
      { justifyContent: "center", alignItems: "center" },
      { justifyContent: "flex-start", alignItems: "flex-end" },
      { flexDirection: "row" }
    ]

    const content = [
      "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vivamus interdum quis ligula vel elementum. Integer non rhoncus purus, eget dignissim ante.",
      "Lorem ipsum dolor sit amet, consectetur adipiscing elit.",
      "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vivamus interdum quis ligula vel elementum. Integer non rhoncus purus, eget dignissim ante. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vivamus interdum quis ligula vel elementum. Integer non rhoncus purus, eget dignissim ante."
    ]

    if (deepNest > 0 && flex) {
      return (
        <div styleName="containerFlex" style={flexProperties[deepNest % 3]}>
          <div styleName="contentFlex" style={flexProperties[deepNest % 3]}>
            { content[deepNest % 3] }
          </div>
          <div styleName="nestedFlex" style={flexProperties[deepNest % 3]}>
            { this.renderComp(deepNest - 1, flex) }
          </div>
        </div>
      )
    }

    if (deepNest > 0 && !flex) {
      return (
        <div styleName="container">
          <div styleName="content">
            Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vivamus interdum quis ligula vel elementum. Integer non rhoncus purus, eget dignissim ante.
          </div>
          <div styleName="nested">
            { this.renderComp(deepNest - 1, flex) }
          </div>
        </div>
      )
    }
  }
}

WithFlex/index.js

import TheComponent from "../Component"

@CSSModules(styles, { allowMultiple: true })
export default class WithFlex extends Component {
  constructor(props) {
    super(props)

    this.state = { render: false }
  }

  render() {
    const {render} = this.state

    // number of components to render
    const arr = _.range(100)

    return (
      <div>
        <div
        style={{ display: "block", padding: 30, lineHeight: "60px" }}
        onClick={() => this.setState({render: !render})}>
            Start Render
        </div>

        { render && arr.map((i) => <TheComponent key={i} deepNest={10} flex={true}/> ) }
      </div>
    )
  }
}

没有Flex/index.js

import TheComponent from "../Component"

@CSSModules(styles, { allowMultiple: true })
export default class WithoutFlex extends Component {
  constructor(props) {
    super(props)

    this.state = { render: false }
  }

  render() {
    const {render} = this.state

    // number of components to renders
    const arr = _.range(100)

    return (
      <div>
        <div
        style={{ display: "block", padding: 30, lineHeight: "60px" }}
        onClick={() => this.setState({render: !render})}>
            Start Render
        </div>

        { render && arr.map((i) => <TheComponent key={i} deepNest={10} flex={false}/> ) }
      </div>
    )
  }
}

Chrome 开发工具时间线的结果。

WithFlex

没有Flex

概括

差别不是那么大。同样在 flexbox 中，我随机放置了可供选择的属性。所以我认为表现还可以。希望它会帮助其他开发人员。

旧的 flexbox (display: box) 比新的 flexbox (display: flex) 慢 2.3 倍。常规块布局（非浮动），通常会比新的 flexbox 快或快，因为它总是单次传递。但是新的 flexbox 应该比使用表格或编写自定义 JS-base 布局代码更快。欲了解更多信息 第一条 第二条