object-browser
v1.0.9
Published
A utility to access object value information using dot and array notations
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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}