textarea在鼠标位置插入文本，替换选中文本

爱被打了一巴掌 2022-01-15 13:55 255阅读 0赞

[为什么80%的码农都做不了架构师？>>> ][80_]  ![hot3.png][]

// 获取textarea光标位置 和 选中文本
    const getTextareaCursor = (textarea: any):void => {
      console.log(textarea)
      let rangeData:any = {
        text: '',
        start: 0,
        end: 0
      }
      if (textarea.setSelectionRange) {
        textarea.focus()
        rangeData.start = textarea.selectionStart
        rangeData.end = textarea.selectionEnd
        rangeData.text = (rangeData.start !== rangeData.end) ? textarea.value.substring(rangeData.start, rangeData.end) : ''
      } else if ((document as any).selection) { // IE
        textarea.focus();
        let i:number = 0
        let oS:any = (document as any).selection.createRange()
        let oR:any = (document as any).body.createTextRange()
        oR.moveToElementText(textarea)
        rangeData.text = oS.text
        rangeData.bookmark = oS.getBookmark()
        for (i = 0; oR.compareEndPoints('StartToStart', oS) < 0 && oS.moveStart('character', -1) !== 0; i++) {
          if (textarea.value.charAt(i) === '/r') {
            i++
          }
        }
        rangeData.start = i
        rangeData.end = rangeData.text.length + rangeData.start
      }
      return rangeData
    }
    // 设置光标回原先位置 在插入文本时调用
    const setTextareaCursor = (textarea:any, rangeData:any) => {
      let oR, start, end
      textarea.focus()
      if (textarea.setSelectionRange) {
        textarea.setSelectionRange(rangeData.start, rangeData.end)
      } else if (textarea.createtextRange) { // IE
        oR = textarea.createTextRange()
        if (textarea.value.length === rangeData.start) {
          oR.collapse(false)
          oR.select()
        } else {
          oR.moveToBookmark(rangeData.bookmark)
          oR.select()
        }
      }
    }
    // 在获取的光标位置插入指定文本 或 替换选定文本
    const addTextareaCursor = (textarea:any, cursor:any, text:string) => {
      // textarea 容器； cursor：光标位置和选中内容； text：要插入的文本
      let oValue, nValue, oR, nStart, nEnd, st
      const sR:any = ''
      setTextareaCursor(textarea, cursor) // 调用获取位置
      if (textarea.setSelectionRange) {
        oValue = textarea.value
        nValue = oValue.substring(0, cursor.start) + text + oValue.substring(cursor.end)
        nStart = nEnd = cursor.start + text.length
        st = textarea.scrollTop
        textarea.value = nValue
        if (textarea.scrollTop !== st) {
          textarea.scrollTop = st
        }
        textarea.setSelectionRange(nStart, nEnd)
      } else if (textarea.createTextRange) { // IE
        sR.document.selection.createRange();
        sR.text = text
        sR.select()
      }
    }
    
    export { getQueryString, getTextareaCursor, setTextareaCursor, addTextareaCursor }

转载于:https://my.oschina.net/lpcysz/blog/3014313

[80_]: https://my.oschina.net/u/2663968/blog/3051541
[hot3.png]: /images/20220115/dff71e4e3de4442c83f39c4011a68b75.png