@walts81/linq-ts/lib/singleOrDefault.js

Typescript/Javascript LINQ implementation library

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.singleOrDefault = void 0;
const _common_1 = require("./_common");
Array.prototype.singleOrDefault = singleOrDefault;
function singleOrDefault(expression, defaultValue = null) {
    const length = this.length;
    if (length === 0)
        return defaultValue;
    if (!expression)
        if (length > 1)
            throw new _common_1.MultipleMatchException();
        else
            return this[0];
    let result = undefined;
    for (let i = 0; i < length; i++) {
        const item = this[i];
        if (expression(item, i)) {
            if (result === undefined)
                result = item;
            else
                throw new _common_1.MultipleMatchException();
        }
    }
    return result || defaultValue;
}
exports.singleOrDefault = singleOrDefault;