index.js

(function() {
    "use strict";

    var typeOf = require('remedial').typeOf;
    var trimWhitespace = require('remove-trailing-spaces');

    function stringify(data) {
        var handlers, indentLevel = '';

        handlers = {
            "undefined": function() {
                // objects will not have `undefined` converted to `null`
                // as this may have unintended consequences
                // For arrays, however, this behavior seems appropriate
                return 'null';
            },
            "null": function() {
                return 'null';
            },
            "number": function(x) {
                return x;
            },
            "boolean": function(x) {
                return x ? 'true' : 'false';
            },
            "string": function(x) {
                // to avoid the string "true" being confused with the
                // the literal `true`, we always wrap strings in quotes
                return JSON.stringify(x);
            },
            "array": function(x) {
                var output = '';

                if (0 === x.length) {
                    output += '[]';
                    return output;
                }

                indentLevel = indentLevel.replace(/$/, '  ');
                x.forEach(function(y, i) {
                    // TODO how should `undefined` be handled?
                    var handler = handlers[typeOf(y)];

                    if (!handler) {
                        throw new Error('what the crap: ' + typeOf(y));
                    }

                    output += '\n' + indentLevel + '- ' + handler(y, true);

                });
                indentLevel = indentLevel.replace(/  /, '');

                return output;
            },
            "object": function(x, inArray, rootNode) {
                var output = '';

                if (0 === Object.keys(x).length) {
                    output += '{}';
                    return output;
                }

                if (!rootNode) {
                    indentLevel = indentLevel.replace(/$/, '  ');
                }

                Object.keys(x).forEach(function(k, i) {
                    var val = x[k],
                        handler = handlers[typeOf(val)];

                    if ('undefined' === typeof val) {
                        // the user should do
                        // delete obj.key
                        // and not
                        // obj.key = undefined
                        // but we'll error on the side of caution
                        return;
                    }

                    if (!handler) {
                        throw new Error('what the crap: ' + typeOf(val));
                    }

                    if (!(inArray && i === 0)) {
                        output += '\n' + indentLevel;
                    }

                    output += k + ': ' + handler(val);
                });
                indentLevel = indentLevel.replace(/  /, '');

                return output;
            },
            "function": function() {
                // TODO this should throw or otherwise be ignored
                return '[object Function]';
            }
        };

        return trimWhitespace(handlers[typeOf(data)](data, true, true) + '\n');
    }

    module.exports.stringify = stringify;
}());