How to group objects with specific key in javaScript - javascript

I want to do a grouping for JavaScript object as age.My JSON is
var jsonObj=[{"name":"john","age":23},{"name":"mark","age":25},{"name":"jeni","age":21}]`
I want to be the group result like here.
[23:{"name":"john","age":23},25:{"name":"mark","age":25},21:{"name":"jeni","age":21}]
Please help me to get a result, I try with map and filter but did not get the result.

Use Array#reduce to group the objects. Because there can multiple people with the same age, collect them into an array under the age property:
var jsonObj=[{"name":"john","age":23},{"name":"mark","age":25},{"name":"poll","age":23},{"name":"jeni","age":21}];
var result = jsonObj.reduce(function(r, o) {
r[o.age] || (r[o.age] = []); // if the age key doesn't exist, set it to be an array
r[o.age].push(o); // push the object into the array
return r;
}, {});
console.log(result);
Or the fancy ES6 one liner version:
var jsonObj=[{"name":"john","age":23},{"name":"mark","age":25},{"name":"poll","age":23},{"name":"jeni","age":21}];
var result = jsonObj.reduce((r, o) => ((r[o.age] || (r[o.age] = [])).push(o), r), {});
console.log(result);

You could take the hash table as result. Then loop and create new arrays for new keys. Later push the object.
var data = [{ name: "john", age: 23 }, { name: "mark", age: 25 }, { name: "poll", age: 23 }, { name: "jeni", age: 21 }],
result = {};
data.forEach(o => (result[o.age] = result[o.age] || []).push(o));
console.log(result);
.as-console-wrapper { max-height: 100% !important; top: 0; }

You can use underscore js to solve this problem.Add underscore js first<script src='https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.3/underscore.js' ></script> then you can simply get the result.
var result=_.indexBy(jsonObj, 'age');

You can try it :
var jsonObj = [{ "name": "john", "age": 23 }, { "name": "mark", "age": 25 }, { "name": "poll", "age": 23 }, { "name": "jeni", "age": 21 }];
let result = {};
jsonObj.forEach(item => {
if(result.hasOwnProperty(item.age)) {
let arr = [];
if(Array.isArray(result[item.age])) {
result[item.age].push(item);
} else {
result[item.age] = [result[item.age], item];
}
} else {
result[item.age] = item;
}
});
console.log(result)

Related

Lodash return object of array that have true value in object [duplicate]

I have an array of objects and I'm wondering the best way to search it. Given the below example how can I search for name = "Joe" and age < 30? Is there anything jQuery can help with or do I have to brute force this search myself?
var names = new Array();
var object = { name : "Joe", age:20, email: "joe#hotmail.com"};
names.push(object);
object = { name : "Mike", age:50, email: "mike#hotmail.com"};
names.push(object);
object = { name : "Joe", age:45, email: "mike#hotmail.com"};
names.push(object);
A modern solution with Array.prototype.filter():
const found_names = names.filter(v => v.name === "Joe" && v.age < 30);
Or if you still use jQuery, you may use jQuery.grep():
var found_names = $.grep(names, function(v) {
return v.name === "Joe" && v.age < 30;
});
You can do this very easily with the [].filter method:
var filterednames = names.filter(function(obj) {
return (obj.name === "Joe") && (obj.age < 30);
});
You can learn more about it on this MDN page.
You could utilize jQuery.filter() function to return elements from a subset of the matching elements.
var names = [
{ name : "Joe", age:20, email: "joe#hotmail.com"},
{ name : "Mike", age:50, email: "mike#hotmail.com"},
{ name : "Joe", age:45, email: "mike#hotmail.com"}
];
var filteredNames = $(names).filter(function( idx ) {
return names[idx].name === "Joe" && names[idx].age < 30;
});
$(filteredNames).each(function(){
$('#output').append(this.name);
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="output"/>
var nameList = [
{name:'x', age:20, email:'x#email.com'},
{name:'y', age:60, email:'y#email.com'},
{name:'Joe', age:22, email:'joe#email.com'},
{name:'Abc', age:40, email:'abc#email.com'}
];
var filteredValue = nameList.filter(function (item) {
return item.name == "Joe" && item.age < 30;
});
//To See Output Result as Array
console.log(JSON.stringify(filteredValue));
You can simply use javascript :)
For those who want to filter from an array of objects using any key:
function filterItems(items, searchVal) {
return items.filter((item) => Object.values(item).includes(searchVal));
}
let data = [
{ "name": "apple", "type": "fruit", "id": 123234 },
{ "name": "cat", "type": "animal", "id": 98989 },
{ "name": "something", "type": "other", "id": 656565 }]
console.log("Filtered by name: ", filterItems(data, "apple"));
console.log("Filtered by type: ", filterItems(data, "animal"));
console.log("Filtered by id: ", filterItems(data, 656565));
filter from an array of the JSON objects:**
var names = [{
name: "Joe",
age: 20,
email: "joe#hotmail.com"
},
{
name: "Mike",
age: 50,
email: "mike#hotmail.com"
},
{
name: "Joe",
age: 45,
email: "mike#hotmail.com"
}
];
const res = _.filter(names, (name) => {
return name.name == "Joe" && name.age < 30;
});
console.log(res);
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.js"></script>
So quick question. What if you have two arrays of objects and you would like to 'align' these object arrays so that you can make sure each array's objects are in the order as the other array's? What if you don't know what keys and values any of the objects inside of the arrays contains... Much less what order they're even in?
So you need a 'WildCard Expression' for your [].filter, [].map, etc. How do you get a wild card expression?
var jux = (function(){
'use strict';
function wildExp(obj){
var keysCrude = Object.keys(obj),
keysA = ('a["' + keysCrude.join('"], a["') + '"]').split(', '),
keysB = ('b["' + keysCrude.join('"], b["') + '"]').split(', '),
keys = [].concat(keysA, keysB)
.sort(function(a, b){ return a.substring(1, a.length) > b.substring(1, b.length); });
var exp = keys.join('').split(']b').join('] > b').split(']a').join('] || a');
return exp;
}
return {
sort: wildExp
};
})();
var sortKeys = {
k: 'v',
key: 'val',
n: 'p',
name: 'param'
};
var objArray = [
{
k: 'z',
key: 'g',
n: 'a',
name: 'b'
},
{
k: 'y',
key: 'h',
n: 'b',
name: 't'
},
{
k: 'x',
key: 'o',
n: 'a',
name: 'c'
}
];
var exp = jux.sort(sortKeys);
console.log('#juxSort Expression:', exp);
console.log('#juxSort:', objArray.sort(function(a, b){
return eval(exp);
}));
You can also use this function over an iteration for each object to create a better collective expression for all of the keys in each of your objects, and then filter your array that way.
This is a small snippet from the API Juxtapose which I have almost complete, which does this, object equality with exemptions, object unities, and array condensation. If these are things you need or want for your project please comment and I'll make the lib accessible sooner than later.
Hope this helps! Happy coding :)
The most straightforward and readable approach will be the usage of native javascript filter method.
Native javaScript filter takes a declarative approach in filtering array elements. Since it is a method defined on Array.prototype, it iterates on a provided array and invokes a callback on it. This callback, which acts as our filtering function, takes three parameters:
element — the current item in the array being iterated over
index — the index or location of the current element in the array that is being iterated over
array — the original array that the filter method was applied on
Let’s use this filter method in an example. Note that the filter can be applied on any sort of array. In this example, we are going to filter an array of objects based on an object property.
An example of filtering an array of objects based on object properties could look something like this:
// Please do not hate me for bashing on pizza and burgers.
// and FYI, I totally made up the healthMetric param :)
let foods = [
{ type: "pizza", healthMetric: 25 },
{ type: "burger", healthMetric: 10 },
{ type: "salad", healthMetric: 60 },
{ type: "apple", healthMetric: 82 }
];
let isHealthy = food => food.healthMetric >= 50;
const result = foods.filter(isHealthy);
console.log(result.map(food => food.type));
// Result: ['salad', 'apple']
To learn more about filtering arrays in functions and yo build your own filtering, check out this article:
https://medium.com/better-programming/build-your-own-filter-e88ba0dcbfae

Return keys and values from multiple object in array [duplicate]

I have an array of objects and I'm wondering the best way to search it. Given the below example how can I search for name = "Joe" and age < 30? Is there anything jQuery can help with or do I have to brute force this search myself?
var names = new Array();
var object = { name : "Joe", age:20, email: "joe#hotmail.com"};
names.push(object);
object = { name : "Mike", age:50, email: "mike#hotmail.com"};
names.push(object);
object = { name : "Joe", age:45, email: "mike#hotmail.com"};
names.push(object);
A modern solution with Array.prototype.filter():
const found_names = names.filter(v => v.name === "Joe" && v.age < 30);
Or if you still use jQuery, you may use jQuery.grep():
var found_names = $.grep(names, function(v) {
return v.name === "Joe" && v.age < 30;
});
You can do this very easily with the [].filter method:
var filterednames = names.filter(function(obj) {
return (obj.name === "Joe") && (obj.age < 30);
});
You can learn more about it on this MDN page.
You could utilize jQuery.filter() function to return elements from a subset of the matching elements.
var names = [
{ name : "Joe", age:20, email: "joe#hotmail.com"},
{ name : "Mike", age:50, email: "mike#hotmail.com"},
{ name : "Joe", age:45, email: "mike#hotmail.com"}
];
var filteredNames = $(names).filter(function( idx ) {
return names[idx].name === "Joe" && names[idx].age < 30;
});
$(filteredNames).each(function(){
$('#output').append(this.name);
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="output"/>
var nameList = [
{name:'x', age:20, email:'x#email.com'},
{name:'y', age:60, email:'y#email.com'},
{name:'Joe', age:22, email:'joe#email.com'},
{name:'Abc', age:40, email:'abc#email.com'}
];
var filteredValue = nameList.filter(function (item) {
return item.name == "Joe" && item.age < 30;
});
//To See Output Result as Array
console.log(JSON.stringify(filteredValue));
You can simply use javascript :)
For those who want to filter from an array of objects using any key:
function filterItems(items, searchVal) {
return items.filter((item) => Object.values(item).includes(searchVal));
}
let data = [
{ "name": "apple", "type": "fruit", "id": 123234 },
{ "name": "cat", "type": "animal", "id": 98989 },
{ "name": "something", "type": "other", "id": 656565 }]
console.log("Filtered by name: ", filterItems(data, "apple"));
console.log("Filtered by type: ", filterItems(data, "animal"));
console.log("Filtered by id: ", filterItems(data, 656565));
filter from an array of the JSON objects:**
var names = [{
name: "Joe",
age: 20,
email: "joe#hotmail.com"
},
{
name: "Mike",
age: 50,
email: "mike#hotmail.com"
},
{
name: "Joe",
age: 45,
email: "mike#hotmail.com"
}
];
const res = _.filter(names, (name) => {
return name.name == "Joe" && name.age < 30;
});
console.log(res);
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.js"></script>
So quick question. What if you have two arrays of objects and you would like to 'align' these object arrays so that you can make sure each array's objects are in the order as the other array's? What if you don't know what keys and values any of the objects inside of the arrays contains... Much less what order they're even in?
So you need a 'WildCard Expression' for your [].filter, [].map, etc. How do you get a wild card expression?
var jux = (function(){
'use strict';
function wildExp(obj){
var keysCrude = Object.keys(obj),
keysA = ('a["' + keysCrude.join('"], a["') + '"]').split(', '),
keysB = ('b["' + keysCrude.join('"], b["') + '"]').split(', '),
keys = [].concat(keysA, keysB)
.sort(function(a, b){ return a.substring(1, a.length) > b.substring(1, b.length); });
var exp = keys.join('').split(']b').join('] > b').split(']a').join('] || a');
return exp;
}
return {
sort: wildExp
};
})();
var sortKeys = {
k: 'v',
key: 'val',
n: 'p',
name: 'param'
};
var objArray = [
{
k: 'z',
key: 'g',
n: 'a',
name: 'b'
},
{
k: 'y',
key: 'h',
n: 'b',
name: 't'
},
{
k: 'x',
key: 'o',
n: 'a',
name: 'c'
}
];
var exp = jux.sort(sortKeys);
console.log('#juxSort Expression:', exp);
console.log('#juxSort:', objArray.sort(function(a, b){
return eval(exp);
}));
You can also use this function over an iteration for each object to create a better collective expression for all of the keys in each of your objects, and then filter your array that way.
This is a small snippet from the API Juxtapose which I have almost complete, which does this, object equality with exemptions, object unities, and array condensation. If these are things you need or want for your project please comment and I'll make the lib accessible sooner than later.
Hope this helps! Happy coding :)
The most straightforward and readable approach will be the usage of native javascript filter method.
Native javaScript filter takes a declarative approach in filtering array elements. Since it is a method defined on Array.prototype, it iterates on a provided array and invokes a callback on it. This callback, which acts as our filtering function, takes three parameters:
element — the current item in the array being iterated over
index — the index or location of the current element in the array that is being iterated over
array — the original array that the filter method was applied on
Let’s use this filter method in an example. Note that the filter can be applied on any sort of array. In this example, we are going to filter an array of objects based on an object property.
An example of filtering an array of objects based on object properties could look something like this:
// Please do not hate me for bashing on pizza and burgers.
// and FYI, I totally made up the healthMetric param :)
let foods = [
{ type: "pizza", healthMetric: 25 },
{ type: "burger", healthMetric: 10 },
{ type: "salad", healthMetric: 60 },
{ type: "apple", healthMetric: 82 }
];
let isHealthy = food => food.healthMetric >= 50;
const result = foods.filter(isHealthy);
console.log(result.map(food => food.type));
// Result: ['salad', 'apple']
To learn more about filtering arrays in functions and yo build your own filtering, check out this article:
https://medium.com/better-programming/build-your-own-filter-e88ba0dcbfae

Javascript Object -Filter and get desired content [duplicate]

I have an array of objects and I'm wondering the best way to search it. Given the below example how can I search for name = "Joe" and age < 30? Is there anything jQuery can help with or do I have to brute force this search myself?
var names = new Array();
var object = { name : "Joe", age:20, email: "joe#hotmail.com"};
names.push(object);
object = { name : "Mike", age:50, email: "mike#hotmail.com"};
names.push(object);
object = { name : "Joe", age:45, email: "mike#hotmail.com"};
names.push(object);
A modern solution with Array.prototype.filter():
const found_names = names.filter(v => v.name === "Joe" && v.age < 30);
Or if you still use jQuery, you may use jQuery.grep():
var found_names = $.grep(names, function(v) {
return v.name === "Joe" && v.age < 30;
});
You can do this very easily with the [].filter method:
var filterednames = names.filter(function(obj) {
return (obj.name === "Joe") && (obj.age < 30);
});
You can learn more about it on this MDN page.
You could utilize jQuery.filter() function to return elements from a subset of the matching elements.
var names = [
{ name : "Joe", age:20, email: "joe#hotmail.com"},
{ name : "Mike", age:50, email: "mike#hotmail.com"},
{ name : "Joe", age:45, email: "mike#hotmail.com"}
];
var filteredNames = $(names).filter(function( idx ) {
return names[idx].name === "Joe" && names[idx].age < 30;
});
$(filteredNames).each(function(){
$('#output').append(this.name);
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="output"/>
var nameList = [
{name:'x', age:20, email:'x#email.com'},
{name:'y', age:60, email:'y#email.com'},
{name:'Joe', age:22, email:'joe#email.com'},
{name:'Abc', age:40, email:'abc#email.com'}
];
var filteredValue = nameList.filter(function (item) {
return item.name == "Joe" && item.age < 30;
});
//To See Output Result as Array
console.log(JSON.stringify(filteredValue));
You can simply use javascript :)
For those who want to filter from an array of objects using any key:
function filterItems(items, searchVal) {
return items.filter((item) => Object.values(item).includes(searchVal));
}
let data = [
{ "name": "apple", "type": "fruit", "id": 123234 },
{ "name": "cat", "type": "animal", "id": 98989 },
{ "name": "something", "type": "other", "id": 656565 }]
console.log("Filtered by name: ", filterItems(data, "apple"));
console.log("Filtered by type: ", filterItems(data, "animal"));
console.log("Filtered by id: ", filterItems(data, 656565));
filter from an array of the JSON objects:**
var names = [{
name: "Joe",
age: 20,
email: "joe#hotmail.com"
},
{
name: "Mike",
age: 50,
email: "mike#hotmail.com"
},
{
name: "Joe",
age: 45,
email: "mike#hotmail.com"
}
];
const res = _.filter(names, (name) => {
return name.name == "Joe" && name.age < 30;
});
console.log(res);
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.js"></script>
So quick question. What if you have two arrays of objects and you would like to 'align' these object arrays so that you can make sure each array's objects are in the order as the other array's? What if you don't know what keys and values any of the objects inside of the arrays contains... Much less what order they're even in?
So you need a 'WildCard Expression' for your [].filter, [].map, etc. How do you get a wild card expression?
var jux = (function(){
'use strict';
function wildExp(obj){
var keysCrude = Object.keys(obj),
keysA = ('a["' + keysCrude.join('"], a["') + '"]').split(', '),
keysB = ('b["' + keysCrude.join('"], b["') + '"]').split(', '),
keys = [].concat(keysA, keysB)
.sort(function(a, b){ return a.substring(1, a.length) > b.substring(1, b.length); });
var exp = keys.join('').split(']b').join('] > b').split(']a').join('] || a');
return exp;
}
return {
sort: wildExp
};
})();
var sortKeys = {
k: 'v',
key: 'val',
n: 'p',
name: 'param'
};
var objArray = [
{
k: 'z',
key: 'g',
n: 'a',
name: 'b'
},
{
k: 'y',
key: 'h',
n: 'b',
name: 't'
},
{
k: 'x',
key: 'o',
n: 'a',
name: 'c'
}
];
var exp = jux.sort(sortKeys);
console.log('#juxSort Expression:', exp);
console.log('#juxSort:', objArray.sort(function(a, b){
return eval(exp);
}));
You can also use this function over an iteration for each object to create a better collective expression for all of the keys in each of your objects, and then filter your array that way.
This is a small snippet from the API Juxtapose which I have almost complete, which does this, object equality with exemptions, object unities, and array condensation. If these are things you need or want for your project please comment and I'll make the lib accessible sooner than later.
Hope this helps! Happy coding :)
The most straightforward and readable approach will be the usage of native javascript filter method.
Native javaScript filter takes a declarative approach in filtering array elements. Since it is a method defined on Array.prototype, it iterates on a provided array and invokes a callback on it. This callback, which acts as our filtering function, takes three parameters:
element — the current item in the array being iterated over
index — the index or location of the current element in the array that is being iterated over
array — the original array that the filter method was applied on
Let’s use this filter method in an example. Note that the filter can be applied on any sort of array. In this example, we are going to filter an array of objects based on an object property.
An example of filtering an array of objects based on object properties could look something like this:
// Please do not hate me for bashing on pizza and burgers.
// and FYI, I totally made up the healthMetric param :)
let foods = [
{ type: "pizza", healthMetric: 25 },
{ type: "burger", healthMetric: 10 },
{ type: "salad", healthMetric: 60 },
{ type: "apple", healthMetric: 82 }
];
let isHealthy = food => food.healthMetric >= 50;
const result = foods.filter(isHealthy);
console.log(result.map(food => food.type));
// Result: ['salad', 'apple']
To learn more about filtering arrays in functions and yo build your own filtering, check out this article:
https://medium.com/better-programming/build-your-own-filter-e88ba0dcbfae

Remove Json object from json array element

var jsonArray = ["test", "test1", "test2"];
var matchedValue = "test1";
I want to remove remove and (matchedValue) from the JsonArray.
How can i delete and return rest of the string
Expected output : ["test", "test2"];
What I am doing :
var setValue = JSON.parse(fetchMethodJsonArray);
dataRemoved = setValue.filter(function(el) {
return el != fetchValue;
});
It is not working
Please tell me the solution Thanks in advance.
// Assuming this is your fetched data
const fetchMethodJsonArray = [{
"val": "One"
}, {
"val": "Two"
}, {
"val": "Three"
}];
var setValue = fetchMethodJsonArray;
const dataRemoved = setValue.filter((el) => {
return el.val !== "One";
});
console.log(dataRemoved);
Answer from what i got..
jsonArray.splice(jsonArray.indexOf('string_to_search'));
It will delete the found item and return remaining array.
You can use this:
const deleteObj = (data, column, search) => {
let result = data.filter(m => m[column] !== search);
return result;
}
When you want to remove an object from JSON array element use this method:
const deleteObj = (data, column, search) => {
let result = data.filter(m => m[column] !== search);
return result;
}
const arr = [
{
name: 'test',
surname: 'test1'
},
{
name: 'test23',
surname: 'newsname'
},
{
name: 'test23',
surname: 'newsname'
}
]
const deleted = deleteObj(arr, 'name', 'test');
console.log(deleted);
In this sample, you will use filter method. Mozilla says about filter:
The filter() method creates a new array with all elements that pass
the test implemented by the provided function.
https://developer.mozilla.org/tr/docs/Web/JavaScript/Reference/Global_Objects/Array/filter
If you are using NodeJs, You can use 'modernarray' which is an small and simple npm package.
https://www.npmjs.com/package/modernarray
Install it by npm install modernarray
let modernarray = require('modernarray');
let myarray = [{
"val": "One"
}, {
"val": "Two"
}, {
"val": "Three"
}];
let outputArray2 = modernarray.popByValue(myarray,{val:"One"})
console.log(outputArray2)

javascript filter array of objects

I have an array of objects and I'm wondering the best way to search it. Given the below example how can I search for name = "Joe" and age < 30? Is there anything jQuery can help with or do I have to brute force this search myself?
var names = new Array();
var object = { name : "Joe", age:20, email: "joe#hotmail.com"};
names.push(object);
object = { name : "Mike", age:50, email: "mike#hotmail.com"};
names.push(object);
object = { name : "Joe", age:45, email: "mike#hotmail.com"};
names.push(object);
A modern solution with Array.prototype.filter():
const found_names = names.filter(v => v.name === "Joe" && v.age < 30);
Or if you still use jQuery, you may use jQuery.grep():
var found_names = $.grep(names, function(v) {
return v.name === "Joe" && v.age < 30;
});
You can do this very easily with the [].filter method:
var filterednames = names.filter(function(obj) {
return (obj.name === "Joe") && (obj.age < 30);
});
You can learn more about it on this MDN page.
You could utilize jQuery.filter() function to return elements from a subset of the matching elements.
var names = [
{ name : "Joe", age:20, email: "joe#hotmail.com"},
{ name : "Mike", age:50, email: "mike#hotmail.com"},
{ name : "Joe", age:45, email: "mike#hotmail.com"}
];
var filteredNames = $(names).filter(function( idx ) {
return names[idx].name === "Joe" && names[idx].age < 30;
});
$(filteredNames).each(function(){
$('#output').append(this.name);
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="output"/>
var nameList = [
{name:'x', age:20, email:'x#email.com'},
{name:'y', age:60, email:'y#email.com'},
{name:'Joe', age:22, email:'joe#email.com'},
{name:'Abc', age:40, email:'abc#email.com'}
];
var filteredValue = nameList.filter(function (item) {
return item.name == "Joe" && item.age < 30;
});
//To See Output Result as Array
console.log(JSON.stringify(filteredValue));
You can simply use javascript :)
For those who want to filter from an array of objects using any key:
function filterItems(items, searchVal) {
return items.filter((item) => Object.values(item).includes(searchVal));
}
let data = [
{ "name": "apple", "type": "fruit", "id": 123234 },
{ "name": "cat", "type": "animal", "id": 98989 },
{ "name": "something", "type": "other", "id": 656565 }]
console.log("Filtered by name: ", filterItems(data, "apple"));
console.log("Filtered by type: ", filterItems(data, "animal"));
console.log("Filtered by id: ", filterItems(data, 656565));
filter from an array of the JSON objects:**
var names = [{
name: "Joe",
age: 20,
email: "joe#hotmail.com"
},
{
name: "Mike",
age: 50,
email: "mike#hotmail.com"
},
{
name: "Joe",
age: 45,
email: "mike#hotmail.com"
}
];
const res = _.filter(names, (name) => {
return name.name == "Joe" && name.age < 30;
});
console.log(res);
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.js"></script>
So quick question. What if you have two arrays of objects and you would like to 'align' these object arrays so that you can make sure each array's objects are in the order as the other array's? What if you don't know what keys and values any of the objects inside of the arrays contains... Much less what order they're even in?
So you need a 'WildCard Expression' for your [].filter, [].map, etc. How do you get a wild card expression?
var jux = (function(){
'use strict';
function wildExp(obj){
var keysCrude = Object.keys(obj),
keysA = ('a["' + keysCrude.join('"], a["') + '"]').split(', '),
keysB = ('b["' + keysCrude.join('"], b["') + '"]').split(', '),
keys = [].concat(keysA, keysB)
.sort(function(a, b){ return a.substring(1, a.length) > b.substring(1, b.length); });
var exp = keys.join('').split(']b').join('] > b').split(']a').join('] || a');
return exp;
}
return {
sort: wildExp
};
})();
var sortKeys = {
k: 'v',
key: 'val',
n: 'p',
name: 'param'
};
var objArray = [
{
k: 'z',
key: 'g',
n: 'a',
name: 'b'
},
{
k: 'y',
key: 'h',
n: 'b',
name: 't'
},
{
k: 'x',
key: 'o',
n: 'a',
name: 'c'
}
];
var exp = jux.sort(sortKeys);
console.log('#juxSort Expression:', exp);
console.log('#juxSort:', objArray.sort(function(a, b){
return eval(exp);
}));
You can also use this function over an iteration for each object to create a better collective expression for all of the keys in each of your objects, and then filter your array that way.
This is a small snippet from the API Juxtapose which I have almost complete, which does this, object equality with exemptions, object unities, and array condensation. If these are things you need or want for your project please comment and I'll make the lib accessible sooner than later.
Hope this helps! Happy coding :)
The most straightforward and readable approach will be the usage of native javascript filter method.
Native javaScript filter takes a declarative approach in filtering array elements. Since it is a method defined on Array.prototype, it iterates on a provided array and invokes a callback on it. This callback, which acts as our filtering function, takes three parameters:
element — the current item in the array being iterated over
index — the index or location of the current element in the array that is being iterated over
array — the original array that the filter method was applied on
Let’s use this filter method in an example. Note that the filter can be applied on any sort of array. In this example, we are going to filter an array of objects based on an object property.
An example of filtering an array of objects based on object properties could look something like this:
// Please do not hate me for bashing on pizza and burgers.
// and FYI, I totally made up the healthMetric param :)
let foods = [
{ type: "pizza", healthMetric: 25 },
{ type: "burger", healthMetric: 10 },
{ type: "salad", healthMetric: 60 },
{ type: "apple", healthMetric: 82 }
];
let isHealthy = food => food.healthMetric >= 50;
const result = foods.filter(isHealthy);
console.log(result.map(food => food.type));
// Result: ['salad', 'apple']
To learn more about filtering arrays in functions and yo build your own filtering, check out this article:
https://medium.com/better-programming/build-your-own-filter-e88ba0dcbfae

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