object-browser

Introduction

Object browser is a tool to access and retrieve intra-object values. It can work exactly like lodash's _.get method and was designed to mimic mongodb's ability to access documents nested in an array. The software was built to work with mongo-query-compiler utility.

Examples

/* sample object to be browsed */

import {browser} from 'object-browser';

let o = { 
  item: {
    type: 'book',
    description: {
      short: 'Some book'
    }
  },
  tags: ['book', 'technical'],
  reviews: undefined,
  store: [{
    number: '222', 
    qty: 51,
    region: 'NE',
    employees: [{
      name: {
        first: 'John',
        last: 'Doe'
      },
      age: 22
    }, {
      name: {
        first: 'Jack',
        last: 'Smith'
      },
      age: 27
    }]
  }, { 
    number: '212', 
    qty: 11,
    employees: [{
      name: {
        first: 'Kate',
        last: 'Jones'
      }
    }]
  }] 
};

Standard object value access

let shortDescription = browser(o, 'item.description.short');
//shortDescription = 'Some book'

Standard array value access

let tag = browser(o, 'tags.1')
//tag = 'technical'

Combined object and array value access

let firstName = browser(o, 'store.0.employees.0.name.first');
//firstName = 'John'

Additionally, access path may be specified as an array of path parts, rather than a dot-notated string.

let firstName = browser(o, ['store', '0', 'employees', '0', 'name', 'first']);
//firstName = 'John'

Access of values of objects nested in an array

let storeNumbers = browser(o, 'store.number');
//storeNumbers = ['222', '212']

Access of values of objects nested across multiple arrays

let employeeNames = browser(o, 'store.employees.name');
//employeeNames = []

store and its nested employees are both arrays and sometimes it may be meaningful to return an array of arrays (e.g., employee records for all stores). This is why object-browser's default behavior is to return an empty array when access is "requested" across several nested arrays. To allow access across multiple nested arrays, the flatten configuration flag should be set.

let employeeFirstNames = browser(o, 'store.employee.name.first', {flatten: true});
//employeeFirstNames = ['John', 'Jack', 'Kate']

Access of a browsed object itself

object-browser is a dependency for mongo-query-compiler. Sometimes the latter has to handle a use-case where an array of primitives is queried against a certain criteria. In that case, mongo-query-compiler has to run assessments on the "object" itself. To access the object itself, a path value of __self can be used.

let __self = browser(o, '__self');
//__self = o

Setting meta-data requests

A developer may instruct object-browser to indicate whether an accessed value exists and whether it has been combined into an array by pulling values of array-nested documents together.

let query = browser(o, 'info.description.full', {combined: true, exists: true});
//query = {value: undefined, combined: false, exists: false}

Note: existence of an object value is confirmed if an object has property that is being accessed. The value itself may be undefined.

let query = browser(o, 'reviews', {exists: true});
//query = {value: undefined, exists: true}