diffusion/src/node_modules/util/string.js

Diffusion JavaScript client

var Set = require('core-js/library/fn/set');

/**
 * Split a string around a given delimiter.
 * <P>
 * This differs from String.split in two ways:
 * <ol>
 * <li>If the input string is empty, this function will return an empty array,
 * not a  single-element array containing an empty string.
 * </li>
 * <li>The string will be split into substrings that terminate with the specified
 * delimiter, rather than splitting immediately when a delimiter is found.
 *
 * @example
 * split("foo/bar/", "/"); // Returns ["foo", "bar"];
 *
 * @example
 * split("foo///", "//"); // Returns ["foo/"];
 *
 * @param {String} str - The value to split
 * @param {String} delim - The delimiter to split on
 * @returns {Array} The split parts
 */
function split(str, delim) {
    if (str === "") {
        return [];
    }

    var parts = [], l = delim.length, i = str.lastIndexOf(delim);

    while (i > -1) {
        parts.push(str.substring(i + l, str.length));
        str = str.substring(0, i);
        i = str.lastIndexOf(delim);
    }

    parts.push(str);

    return parts.reverse();
}

function isQuote(c) {
    return c === "'" || c === '"';
}


/**
 * Converts a formatted multi value property to an array.
 * <p>
 * Unescapes any escaped characters in the string.
 *
 * @param {String} stringValue the string with quoted substrings separated by whitespace or
 *        commas
 * @return {Array<String>} array of strings
 */
function stringToArray(stringValue) {

    var arr = [];
    var part = "";
    var pos = 0;
    var escaped = false;

    OUTER_LOOP:
    for (; pos < stringValue.length; pos++) {
        var c = stringValue[pos];
        if (isQuote(c)) {
            pos++;
            part = "";
            escaped = false;
            for (; pos < stringValue.length; pos++) {
                var vc = stringValue[pos];
                if (escaped) {
                    part += vc;
                    escaped = false;
                }
                else if (vc === '\\') {
                    escaped = true;
                }
                else if (vc === c) {
                    arr.push(part);
                    continue OUTER_LOOP;
                }
                else {
                    part += vc;
                }
            }
            throw new Error("Mis-quoted input");
        }
    }
    return arr;
}

/**
 * Inserts an escape character '\' before any of the special characters ' "
 * or \.
 * @param {String} string the string to be escaped
 * @returns {String} the string value with escape characters inserted as appropriate
 */
function escape(string) {
    for (var i = 0; i < string.length; i++) {
        var ci = string.charAt(i);
        if (ci === '"' || ci === '\\' || ci === '\'') {
            var sb = "";
            for (var j = 0; j < string.length; j++) {
                var cj = string.charAt(j);
                switch(cj) {
                    case '\\':
                        sb += "\\\\";
                        break;
                    case '"':
                        sb += "\\\"";
                        break;
                    case '\'':
                        sb += "\\'";
                        break;
                    default:
                        sb += cj;
                        break;
                }
            }
            return sb;
        }
    }
    return string;
}

/**
 * Converts a formatted multi value property to an immutable set.
 * <p>
 * Unescapes any escaped characters in the string.
 * @param {String} stringValue the string with quoted substrings separated by whitespace or
 *        commas
 * @return {Array<String>} set of strings
 */
function stringToSet(stringValue) {
    return new Set(stringToArray(stringValue));
}

/**
 * Converts a set of values to a canonicalised property string
 * representation, escaping as required.
 * <p>
 * Uses comma separators and single quotes.
 *
 * @param {Set<String>|Array<String>} values a set of roles
 *
 * @return {String} a string with each of the members escaped, quoted and concatenated
 */
function collectionToString(values) {
    var arr = [];
    values.forEach(function(string) {
        arr.push('\"' + escape(string) + '\"');
    });

    return arr.join(",");
}

module.exports = {
    split : split,
    stringToArray: stringToArray,
    stringToSet: stringToSet,
    collectionToString: collectionToString,
    escape: escape
};