---

Motivation

For example, I didn't like to write the following code every time...　humm...

const value = {
    children: {
        john: {hobby: [{name: "Cycling"}, {name: "Dance"}], pet: [{type: "dog", name: "Max"}]},
        tom: {hobby: [{name: "Squash"}], pet: [{type: "cat", name: "Chloe"}]}
    }
};

var answer = undefined;
if (value.children) {
    if (value.children.john) {
        if (value.children.john.hobby) {
            if (Array.isArray(value.children.john.hobby)) {
                if (value.children.john.hobby.length >= 2) {
                    if (value.children.john.hobby[1].name) {
                        answer = value.children.john.hobby[1].name;
                    }
                }
            }
        }
    }
}

The ugly thing above is nice if you can write it like this, right?

const {AttrPath}: any = require("attrpath");

var answer = AttrPath.traverse(value, ".children.john.hobby[1].name");

Features

Safely traverse the object path using the given path string. Also, an array may be included in the middle of the path.

Installation

npm install atttrpath

Usage

API

const {AttrPath}: any = require("attrpath");
// or
import {AttrPath} from 'attrpath';

traverse value.

params

    object: any   Target Object.
    path: string  Traverse path.　The beginning of the path is always ".".
                   e.g.  ".cat.eye.left",  ".dog['leg'][1].pad"  

    result: any　　　Objects obtained as a result of traverse.

AttrPath.traverse(object: any, path: string): any;

path is valid?

params

    path: string  Traverse path.

    result: boolean　　path is grammatically correct?　

AttrPath.is_valid(path: string): boolean;

Exsample

const {AttrPath}: any = require("attrpath");

const value = {
    children: {
        john: {
            hobby: [{name: "Cycling"}, {name: "Dance"}],
            pet: [{type: "dog", name: "Max"}]
        },
        tom: {
            hobby: [{name: "Squash"}],
            pet: [{type: "cat", name: "Chloe"}]
        }
    }
};

console.log(AttrPath.traverse(value, '.children.john.hobby[0].name'))

> "Max"

console.log(AttrPath.traverse(value, '.children.john.hobby[1].name'))

> undefined

console.log(AttrPath.is_valid('.children.john.hobby[0].name'))

> true

console.log(AttrPath.is_valid('.children.john.hobby[0]..name'))

> false

Example Data

    const value = {
        children: {
            john: {
                hobby: [{name: "Cycling"}, {name: "Dance"}],
                pet: [{type: "dog", name: "Max"}]
            },
            tom: {
                hobby: [{name: "Squash"}],
                pet: [{type: "cat", name: "Chloe"}]
            }
        }
    };

ESModule

import {AttrPath} from 'attrpath';

    AttrPath.traverse(value, '.children')
    AttrPath.is_valid('.children["john"].hobby[1].name')

CommonJS

const {AttrPath} = require('attrpath');

    AttrPath.traverse(value, '.children');
    AttrPath.is_valid('.children["john"].hobby[1].name')

Note

See demo.md for unclear cases.

Author

info@seventh-code.com

License

"AttrPath" is under MIT license.