Function indentLine

mini-code-editor/cm/lib/codemirror.js:1317–1348

(n, how)

    }

    function indentLine(n, how) {
      if (!how) how = "add";
      if (how == "smart") {
        if (!mode.indent) how = "prev";
        else var state = getStateBefore(n);
      }

      var line = getLine(n), curSpace = line.indentation(options.tabSize),
          curSpaceString = line.text.match(/^\s*/)[0], indentation;
      if (how == "prev") {
        if (n) indentation = getLine(n-1).indentation(options.tabSize);
        else indentation = 0;
      }
      else if (how == "smart") indentation = mode.indent(state, line.text.slice(curSpaceString.length), line.text);
      else if (how == "add") indentation = curSpace + options.indentUnit;
      else if (how == "subtract") indentation = curSpace - options.indentUnit;
      indentation = Math.max(0, indentation);
      var diff = indentation - curSpace;

      if (!diff) {
        if (sel.from.line != n && sel.to.line != n) return;
        var indentString = curSpaceString;
      }
      else {
        var indentString = "", pos = 0;
        if (options.indentWithTabs)
          for (var i = Math.floor(indentation / options.tabSize); i; --i) {pos += options.tabSize; indentString += "\t";}
        while (pos < indentation) {++pos; indentString += " ";}
      }

      replaceRange(indentString, {line: n, ch: 0}, {line: n, ch: curSpaceString.length});
    }

    function loadMode() {
      mode = CodeMirror.getMode(options, options.mode);