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build/lib/codemirror/addon/display/placeholder.js 1.92 KB
5a739853   patrick.he   commit
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  // CodeMirror, copyright (c) by Marijn Haverbeke and others
  // Distributed under an MIT license: http://codemirror.net/LICENSE
  
  (function(mod) {
    if (typeof exports == "object" && typeof module == "object") // CommonJS
      mod(require("../../lib/codemirror"));
    else if (typeof define == "function" && define.amd) // AMD
      define(["../../lib/codemirror"], mod);
    else // Plain browser env
      mod(CodeMirror);
  })(function(CodeMirror) {
    CodeMirror.defineOption("placeholder", "", function(cm, val, old) {
      var prev = old && old != CodeMirror.Init;
      if (val && !prev) {
        cm.on("blur", onBlur);
        cm.on("change", onChange);
        onChange(cm);
      } else if (!val && prev) {
        cm.off("blur", onBlur);
        cm.off("change", onChange);
        clearPlaceholder(cm);
        var wrapper = cm.getWrapperElement();
        wrapper.className = wrapper.className.replace(" CodeMirror-empty", "");
      }
  
      if (val && !cm.hasFocus()) onBlur(cm);
    });
  
    function clearPlaceholder(cm) {
      if (cm.state.placeholder) {
        cm.state.placeholder.parentNode.removeChild(cm.state.placeholder);
        cm.state.placeholder = null;
      }
    }
    function setPlaceholder(cm) {
      clearPlaceholder(cm);
      var elt = cm.state.placeholder = document.createElement("pre");
      elt.style.cssText = "height: 0; overflow: visible";
      elt.className = "CodeMirror-placeholder";
      elt.appendChild(document.createTextNode(cm.getOption("placeholder")));
      cm.display.lineSpace.insertBefore(elt, cm.display.lineSpace.firstChild);
    }
  
    function onBlur(cm) {
      if (isEmpty(cm)) setPlaceholder(cm);
    }
    function onChange(cm) {
      var wrapper = cm.getWrapperElement(), empty = isEmpty(cm);
      wrapper.className = wrapper.className.replace(" CodeMirror-empty", "") + (empty ? " CodeMirror-empty" : "");
  
      if (empty) setPlaceholder(cm);
      else clearPlaceholder(cm);
    }
  
    function isEmpty(cm) {
      return (cm.lineCount() === 1) && (cm.getLine(0) === "");
    }
  });