https://wordtohtml.net/js/codemirror5659/addon/display/placeholder.js?v=1663685212

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});