/**
 * Get the property named by "name" of the given object
 * If an array is indexed using a string key then a map is done and an array with the content of the properties with that name are returned
 * Ex: docs.text => will return an array of text properties of the docs array
 * @param object the object
 * @param name the name of the property.
 * @returns the property value
 */
function _prop(object: any, name: string) {
    if (object === undefined) {
        return undefined;
    }
    if (Array.isArray(object)) {
        const index = +name;
        if (isNaN(index)) {
            // map array to property
            return object.map(item => item[name]);
        } else {
            return object[index];
        }
    } else {
        return object[name];
    }

}

export function resolveField(object: any, path: string[]) {
    let p = object as any;
    if (!p) return p;
    if (!path.length) return p;
    const last = path.length - 1;
    for (let i = 0; i < last; i++) {
        p = _prop(p, path[i])
        if (!p) {
            return undefined;
        }
    }
    return _prop(p, path[last]);
}