pro-docs/libs/codemirror/addon/edit/trailingspace.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) {
    CodeMirror.defineOption('showTrailingSpace', false, function (cm, val, prev) {
        if (prev == CodeMirror.Init) prev = false
        if (prev && !val) cm.removeOverlay('trailingspace')
        else if (!prev && val)
            cm.addOverlay({
                token: function (stream) {
                    for (var l = stream.string.length, i = l; i && /\s/.test(stream.string.charAt(i - 1)); --i) {}
                    if (i > stream.pos) {
                        stream.pos = i
                        return null
                    }
                    stream.pos = l
                    return 'trailingspace'
                },
                name: 'trailingspace',
            })
    })
})