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   1  // CodeMirror, copyright (c) by Marijn Haverbeke and others
   2  // Distributed under an MIT license: https://codemirror.net/5/LICENSE
   3  
   4  (function(mod) {
   5    if (typeof exports == "object" && typeof module == "object") // CommonJS
   6      mod(require("../../lib/codemirror"));
   7    else if (typeof define == "function" && define.amd) // AMD
   8      define(["../../lib/codemirror"], mod);
   9    else // Plain browser env
  10      mod(CodeMirror);
  11  })(function(CodeMirror) {
  12    CodeMirror.defineOption("placeholder", "", function(cm, val, old) {
  13      var prev = old && old != CodeMirror.Init;
  14      if (val && !prev) {
  15        cm.on("blur", onBlur);
  16        cm.on("change", onChange);
  17        cm.on("swapDoc", onChange);
  18        CodeMirror.on(cm.getInputField(), "compositionupdate", cm.state.placeholderCompose = function() { onComposition(cm) })
  19        onChange(cm);
  20      } else if (!val && prev) {
  21        cm.off("blur", onBlur);
  22        cm.off("change", onChange);
  23        cm.off("swapDoc", onChange);
  24        CodeMirror.off(cm.getInputField(), "compositionupdate", cm.state.placeholderCompose)
  25        clearPlaceholder(cm);
  26        var wrapper = cm.getWrapperElement();
  27        wrapper.className = wrapper.className.replace(" CodeMirror-empty", "");
  28      }
  29  
  30      if (val && !cm.hasFocus()) onBlur(cm);
  31    });
  32  
  33    function clearPlaceholder(cm) {
  34      if (cm.state.placeholder) {
  35        cm.state.placeholder.parentNode.removeChild(cm.state.placeholder);
  36        cm.state.placeholder = null;
  37      }
  38    }
  39    function setPlaceholder(cm) {
  40      clearPlaceholder(cm);
  41      var elt = cm.state.placeholder = document.createElement("pre");
  42      elt.style.cssText = "height: 0; overflow: visible";
  43      elt.style.direction = cm.getOption("direction");
  44      elt.className = "CodeMirror-placeholder CodeMirror-line-like";
  45      var placeHolder = cm.getOption("placeholder")
  46      if (typeof placeHolder == "string") placeHolder = document.createTextNode(placeHolder)
  47      elt.appendChild(placeHolder)
  48      cm.display.lineSpace.insertBefore(elt, cm.display.lineSpace.firstChild);
  49    }
  50  
  51    function onComposition(cm) {
  52      setTimeout(function() {
  53        var empty = false
  54        if (cm.lineCount() == 1) {
  55          var input = cm.getInputField()
  56          empty = input.nodeName == "TEXTAREA" ? !cm.getLine(0).length
  57            : !/[^\u200b]/.test(input.querySelector(".CodeMirror-line").textContent)
  58        }
  59        if (empty) setPlaceholder(cm)
  60        else clearPlaceholder(cm)
  61      }, 20)
  62    }
  63  
  64    function onBlur(cm) {
  65      if (isEmpty(cm)) setPlaceholder(cm);
  66    }
  67    function onChange(cm) {
  68      var wrapper = cm.getWrapperElement(), empty = isEmpty(cm);
  69      wrapper.className = wrapper.className.replace(" CodeMirror-empty", "") + (empty ? " CodeMirror-empty" : "");
  70  
  71      if (empty) setPlaceholder(cm);
  72      else clearPlaceholder(cm);
  73    }
  74  
  75    function isEmpty(cm) {
  76      return (cm.lineCount() === 1) && (cm.getLine(0) === "");
  77    }
  78  });