data-expand-resolver.js

// MOST Web Framework 2.0 Codename Blueshift BSD-3-Clause license Copyright (c) 2017-2022, THEMOST LP All rights reserved
/*eslint no-var: "off"*/
// noinspection ES6ConvertVarToLetConst

var _ = require('lodash');
/**
 * @param {string} s
 * @returns {Array}
 * @private
 */
function testSplitExpandExpression(s) {
    var ix = 0;
    var paren = -1, charAt, ix1 = -1,
        isLiteral = false,
        lastSplitIndex = 0,
        hasParen = false,
        matches = [],
        match = null;
    while(ix<s.length) {
        charAt=s.charAt(ix);
        if ((charAt==='(') && !isLiteral) {
            if (paren<0) {
                match = [];
                match[0] = s.substr(lastSplitIndex, ix-lastSplitIndex);
                paren = 0;
            }
            if (ix1 === -1) { ix1 = ix; }
            hasParen = true;
            paren += 1;
        }
        else if ((charAt===')') && !isLiteral) {
            if (paren>0) { paren -= 1; }
        }
        else if (charAt==='\'') {
            isLiteral = !isLiteral;
        }
        else if ((charAt === ',') && (paren === -1)) {
            if (match==null) {
                matches.push([s.substr(lastSplitIndex, ix-lastSplitIndex)]);
            }
            lastSplitIndex = ix+1;
        }

        if ((ix === s.length - 1) && (paren === -1)) {
            matches.push([s.substr(lastSplitIndex, ix-lastSplitIndex+1)]);
            match = null;
        }
        else if (paren === 0) {
            match = match || [ ];
            match[1] = s.substr(ix1+1, ix-ix1-1);
            matches.push(match);
            paren = -1;
            ix1 = -1;
        }
        ix += 1;
    }
    return matches;
}

/**
 * @constructor
 */
function DataExpandResolver() {
    //
}
/**
 * Tests a string expression and returns an array of matched expandable entities
 * @param {string} s
 */
DataExpandResolver.prototype.testExpandExpression = function(s) {
    if (_.isNil(s)) {
        return [];
    }
    var result = [], reOptions = /(;|^)(\$expand|\$filter|\$levels|\$orderby|\$groupby|\$select|\$top|\$skip|\$search|\$count)=(.*?)(;\$|$)/ig;
    var matches = testSplitExpandExpression(s);
    for (var i = 0; i < matches.length; i++) {
        var match = matches[i];
        if (typeof match[1] === 'undefined') {
            result.push({ name:match[0].replace(/^\s+|\s+$/,'') });
        }
        else {
            var expand = { };
            expand['name'] = match[0].replace(/^\s+|\s+$/,'');
            reOptions.lastIndex = 0;
            var params = { };
            var expandOptions = match[1];
            var matchOption = reOptions.exec(expandOptions);
            while(matchOption) {
                if (matchOption[3]) {
                    params[matchOption[2]] = matchOption[3];
                    reOptions.lastIndex = reOptions.lastIndex-2;
                }
                matchOption = reOptions.exec(expandOptions);
            }
            expand.options = params;
            result.push(expand);
        }
    }
    return result;
};

/**
 * Tests a string expression and returns an array of matched expandable entities
 * @param {string} s
 */
 DataExpandResolver.prototype.test = function(s) {
    return this.testExpandExpression(s);
 }


if (typeof exports !== 'undefined')
{
    module.exports = {
        DataExpandResolver,
        testExpandExpression: function(s) {
            return DataExpandResolver.prototype.testExpandExpression(s);
        }
    };
}