Underscore.js(_) : Difference between _.where() and _.findwhere()

Underscore.js is a utility-belt JavaScript library for JavaScript that provides a lot of the functional programming. You can easily manipulate data collection to sort and display it.

_.where ():  

where() function always return the object or list of object contains the specific property from collection of object.

Syntax:

_.where(list, filters);

·         list – collection of item

·         filters – parameters which contains conditions

Here is a collection of objects:

var goal = [

    {

        "category": "education",

        "title": "Charlie University",

        "description": "Lorem ipsum dolor sit amet",

        "date": "01/03/2020",

        "value": 50000,

        "achievability": 2,

        "experimental_achievability": 3,

        "suggested": false,

        "accounts": [],

        "articles": [],

        "related_goals": [],

        "id": "1"

    },

    {

        "category": "education",

        "title": "Charlie University",

        "description": "Lorem ipsum dolor sit amet",

        "date": "01/03/2020",

        "value": 50000,

        "achievability": 3,

        "experimental_achievability": 3,

        "suggested": false,

        "accounts": [],

        "articles": [],

        "related_goals": [],

        "id": "2"

    },

    {

        "category": "education",

        "title": "Charlie University",

        "description": "Lorem ipsum dolor sit amet",

        "date": "01/03/2020",

        "value": 50000,

        "achievability": 2,

        "experimental_achievability": 3,

        "suggested": false,

        "accounts": [],

        "articles": [],

        "related_goals": [],

        "id": "3"

    },

    {

        "category": "education",

        "title": "Charlie University",

        "description": "Lorem ipsum dolor sit amet",

        "date": "01/03/2020",

        "value": 50000,

        "achievability": 3,

        "experimental_achievability": 3,

        "suggested": false,

        "accounts": [],

        "articles": [],

        "related_goals": [],

        "id": "4"

    }

]

var filteredGoal = _.where(goal, { achievability: "3" });

filteredGoal is having all matching objects, which have achievability property value 3.

[

    {

        "category": "education",

        "title": "Charlie University",

        "description": "Lorem ipsum dolor sit amet",

        "date": "01/03/2020",

        "value": 50000,

        "achievability": 3,

        "experimental_achievability": 3,

        "suggested": false,

        "accounts": [],

        "articles": [],

        "related_goals": [],

        "id": "2"

    },

    {

        "category": "education",

        "title": "Charlie University",

        "description": "Lorem ipsum dolor sit amet",

        "date": "01/03/2020",

        "value": 50000,

        "achievability": 3,

        "experimental_achievability": 3,

        "suggested": false,

        "accounts": [],

        "articles": [],

        "related_goals": [],

        "id": "4"

    }

]

_.findwhere() : findwhere () function always returns the first matched object in collection.

Syntax:

_. findwhere (list, filters);

·         list – collection of item

·         filters – parameters which contains conditions

var filteredGoal = _.findwhere(goal, { achievability: "3" });

filteredGoal is having only first matching record of goal collections

    {

        "category": "education",

        "title": "Charlie University",

        "description": "Lorem ipsum dolor sit amet",

        "date": "01/03/2020",

        "value": 50000,

        "achievability": 3,

        "experimental_achievability": 3,

        "suggested": false,

        "accounts": [],

        "articles": [],

        "related_goals": [],

        "id": "2"

    }

Additional link: 

http://underscorejs.org/#where