pro-docs/libs/codemirror/addon/fold/indent-fold.js

// CodeMirror, copyright (c) by Marijn Haverbeke and others
// Distributed under an MIT license: https://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)
    // Plain browser env
    else mod(CodeMirror)
})(function (CodeMirror) {
    'use strict'

    function lineIndent(cm, lineNo) {
        var text = cm.getLine(lineNo)
        var spaceTo = text.search(/\S/)
        if (spaceTo == -1 || /\bcomment\b/.test(cm.getTokenTypeAt(CodeMirror.Pos(lineNo, spaceTo + 1)))) return -1
        return CodeMirror.countColumn(text, null, cm.getOption('tabSize'))
    }

    CodeMirror.registerHelper('fold', 'indent', function (cm, start) {
        var myIndent = lineIndent(cm, start.line)
        if (myIndent < 0) return
        var lastLineInFold = null

        // Go through lines until we find a line that definitely doesn't belong in
        // the block we're folding, or to the end.
        for (var i = start.line + 1, end = cm.lastLine(); i <= end; ++i) {
            var indent = lineIndent(cm, i)
            if (indent == -1) {
            } else if (indent > myIndent) {
                // Lines with a greater indent are considered part of the block.
                lastLineInFold = i
            } else {
                // If this line has non-space, non-comment content, and is
                // indented less or equal to the start line, it is the start of
                // another block.
                break
            }
        }
        if (lastLineInFold)
            return {
                from: CodeMirror.Pos(start.line, cm.getLine(start.line).length),
                to: CodeMirror.Pos(lastLineInFold, cm.getLine(lastLineInFold).length),
            }
    })
})