Gets the value deep within a path of object. If at any point in the path the key does not exist. We return undefined. If we have a default value and the path does not exist return that default value.

deep.get.js

/**
 * Gets the value deep within a path of object.
 * If at any point in the path the key does not exist. We return undefined.
 * If we have a default value and the path does not exist return that default value.
 *
 * This allows you to avoid constantly checking for properties along the way like
 * `this.state.wave && this.state.wave.data && this.state.wave.data.companyName`
 *
 * @example get(this, "state.wave.data.companyName") // can return undefined
 * @example get(this, "state.companyOptions", []); // always returns an array.
 *
 * @param {Object} target - An object with deep children.
 * @param {String} path - A dot delimited string representation of the path to follow.
 * @param {*} defaultValue - A return value for when nthe path does not exist.
 * @returns {*} Either the value at the end of the path, the default vlaue, or undefined. 
 */
export function get(target, path, defaultValue) {
    const result = path
        .split(".")
        .reduce((obj, key) => (obj || {})[key], target);

    return result === undefined ? defaultValue : result;
}

deep.get.ts

/**
 * Gets the value deep within a path of object.
 * If at any point in the path the key does not exist. We return undefined.
 * If we have a default value and the path does not exist return that default value.
 *
 * This allows you to avoid constantly checking for properties along the way like
 * `this.state.wave && this.state.wave.data && this.state.wave.data.companyName`
 *
 * @example get(this, "state.wave.data.companyName") // can return undefined
 * @example get(this, "state.companyOptions", []); // always returns an array.
 */
export function get(target: Record<string,any>, path: string, defaultValue?: any): any {
    const result = path
        .split(".")
        .reduce((obj: Record<string,any>, key: string) => (obj || {})[key], target);

    return result === undefined ? defaultValue : result;
}