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How to classify arrays and form new arrays

In my project, I need to classify an array and convert it to another type of array.
The difficulty I encountered was that there was no way to use concise and efficient execution. The following are my input and output:
const input = [{
"type": 1,
"color": "Red(268)"
},
{
"type": 1,
"color": "Blue(583)"
},
{
"type": 2,
"color": "Blue(185)"
},
{
"type": 4,
"color": "Red(326)"
},
{
"type": 4,
"color": "Blue(967)"
},
{
"type": 5,
"color": "Red(863)"
}
]
const output = [
"Type 1: Red(268), Blue(583)",
"Type 2: Blue(185)",
"Type 4: Red(326), Blue(967)",
"Type 5: Red(863)"
]
The following is my method. I use the set() to find out the number of types, and then use for loop to convert it into a string and push into the array, but it cannot be executed continuously, so my function cannot get the correct result, and it is not efficient.
this.ty = 1;
this.result = [];
const set = new Set();
const length = input.filter(item => !set.has(item.type) ? set.add(item.type) : false).length + 1;
for (let i = 1; i < length; i++) {
const temp = input.filter(x => {
return x.type === ty;
})
if (temp.length < 2) {
this.result.push(`Type ${ty}: ${temp[0].color}`);
} else {
this.result.push(`Type ${ty}: ${temp[0].color}, ${temp[1].color}`);
}
this.ty = i + 1;
}
This problem has troubled me for a long time. Can someone provide an easier way to convert this array? Thank you for your help.
const input = [{
"type": 1,
"color": "Red(268)"
},
{
"type": 1,
"color": "Blue(583)"
},
{
"type": 2,
"color": "Blue(185)"
},
{
"type": 4,
"color": "Red(326)"
},
{
"type": 4,
"color": "Blue(967)"
},
{
"type": 5,
"color": "Red(863)"
}
]
console.log('input', input);
this.ty = 1;
this.result = [];
const set = new Set();
const length = input.filter(item => !set.has(item.type) ? set.add(item.type) : false).length + 1;
for (let i = 1; i < length; i++) {
const temp = input.filter(x => {
return x.type === ty;
})
if (temp.length < 2) {
this.result.push(`Type ${ty}: ${temp[0].color}`);
} else {
this.result.push(`Type ${ty}: ${temp[0].color}, ${temp[1].color}`);
}
this.ty = i + 1;
}
console.log('result', this.result);
// output
/* const output = [
"Type 1: Red(268), Blue(583)",
"Type 2: Blue(185)",
"Type 4: Red(326), Blue(967)",
"Type 5: Red(863)"
] */

You can use the Array.reduce() function to iterate your array and construct a new object.
const input = [{
"type": 1,
"color": "Red(268)"
},
{
"type": 1,
"color": "Blue(583)"
},
{
"type": 2,
"color": "Blue(185)"
},
{
"type": 4,
"color": "Red(326)"
},
{
"type": 4,
"color": "Blue(967)"
},
{
"type": 5,
"color": "Red(863)"
}
];
const mappedInput = input.reduce((grouped, {
type,
color
}) => {
if (!grouped.hasOwnProperty(type)) {
grouped[type] = `Type ${type}: ${color}`;
} else {
grouped[type] += `, ${color}`;
}
return grouped;
}, {});
console.log(Object.values(mappedInput));
We use an object to provide efficient key lookup and at the end, retrieve just the array of strings that we need.

You could reduce over the array to create an object that uses the type as a key and an array as a value, pushing new instances into the array with each iteration.
Then map over the Object.entries to produce a new array of strings.
const input = [{"type":1,"color":"Red(268)"},{"type":1,"color":"Blue(583)"},{"type":2,"color":"Blue(185)"},{"type":4,"color":"Red(326)"},{"type":4,"color":"Blue(967)"},{"type":5,"color":"Red(863)"}];
const out = input.reduce((acc, c) => {
const [ key, value ] = Object.values(c);
acc[key] = acc[key] || [];
acc[key].push(value);
return acc;
}, {});
const result = Object.entries(out).map(([key, value]) => {
return `Type ${key}: ${value.join(', ')}`
});
console.log(result);

Here's a simple, functional solution:
// Get list of unique input types
const types = Array.from(new Set(input.map(x => x.type)));
// Map over unique types, filter for matching inputs, yield all colors
const output = types.map(type => `Type ${type}: ${input.filter(x => x.type == type).map(x => x.color).join(', ')}`);

This is the Dynamic Solution for your problem.
let output = input.map(d => {
let k = Object.keys(d);
let v = Object.values(d)
let text = '';
for (var i in k) {
text += `${k[i]}: ${v[i]}, `
}
text = text.substring(0, text.length - 1);
return text })

How to generate minimum-size Javascript object?

How can I create a minimum-sized Javascript serialization of a Javascript object? Essentially a JSON.stringify with all unnecessary quotes removed. (Only basic JSON data types need to be supported, not Dates etc.)
For example, the JSON:
{
"pi": 3.14,
"e!": 4.26
}
would become:
{pi:3.14,"e!":4.26}
Edit: The result is not valid JSON, but is valid Javascript.

Copied from https://stackoverflow.com/a/11233515/916000 and modified:
function stringify(obj_from_json) {
if (typeof obj_from_json !== "object") {
return JSON.stringify(obj_from_json);
} else {
if (Array.isArray(obj_from_json)) {
// if the array contains an object
var arr = [];
for (var i = 0, len = obj_from_json.length; i < len; i++) {
arr.push(stringify(obj_from_json[i]));
}
return "[" + arr.join(",") + "]";
} else {
var props = Object
.keys(obj_from_json)
.map(function(key) {
return (new RegExp(/^[1-9a-zA-Z_$][a-zA-Z0-9_$.]*$/).test(key) ? key : "\"" + key + "\"") + ":" + stringify(obj_from_json[key]);
}).join(",");
return "{" + props + "}";
}
}
}
console.log(stringify({
"pi": 3.14,
"e!": 4.26
}));
console.log(stringify([{
"adjacencies": [{
"nodeTo": "graphnode2",
"nodeFrom": "graphnode1",
"data": {
"$color": "#557EAA"
}
}],
"data": {
"$color": "#EBB056",
"$type": "triangle",
"$dim": 9
},
"id": "graphnode1",
"name": "graphnode1"
}, {
"adjacencies": [],
"data": {
"$color": "#EBB056",
"$type": "triangle",
"$dim": 9
},
"id": "graphnode2",
"name": "graphnode2"
}]));
console.log(stringify({1: 2}));
console.log(stringify({"000": 42}));
console.log(stringify({1.26: 42}));
Edit: Added object array support.
Edit: Fixed array conversion.

Single variable to stand in for multiple key names - javascript

I have an array, something like this:
array =
[
{
"type": "apple",
"color": "red",
"id": "redApple"
},
{
"type": "grape",
"color": "green",
"id": "greenGrape",
"options": [
{
"bunchName": "bunch1",
"size": "8"
},
{
"bunchName": "bunch2",
"size": "10"
},
{
"bunchName": "bunch3",
"size": "5"
}
]
}
]
I have a function that searches for values in the array.
function findValue (index, key) {
return array[index][key];
}
var value = findValue(0, "id");
// returns redApple
Is there a way I could pass a single argument to the function if I wanted to find something deeper in the array? For example, if I wanted to find "bunchName" could I pass it something like 1, "options[0].bunchName" and get back "bunch1"?
I want a function that can handle multiple keys. In my real project sometimes I'm looking for something on the first level, sometimes I'm looking on the second level, sometimes the third level, etc.
jQuery can be used if for some reason that would help.

You could take the string, replace the brackets, split the string and reduce the path for the result. The function uses a default object for missing or not given properties.
function getValue(object, path) {
return path
.replace(/\[/g, '.')
.replace(/\]/g, '')
.split('.')
.reduce(function (o, k) { return (o || {})[k]; }, object);
}
function findValue(index, path) {
return getValue(array[index], path);
}
var array = [{ type: "apple", color: "red", id: "redApple" }, { type: "grape", color: "green", id: "greenGrape", options: [{ bunchName: "bunch1", size: "8" }, { bunchName: "bunch2", size: "10" }, { bunchName: "bunch3", size: "5" }] }];
console.log(findValue(1, "options[0].bunchName"));

From what I understand, output of findValue(object, "bunchName"); should be "bunch3", where object is array in OP's example.
var object =
[
{
"type": "apple",
"color": "red",
"id": "redApple"
},
{
"type": "grape",
"color": "green",
"id": "greenGrape",
"options": [
{
"bunchName": "bunch1",
"size": "8"
},
{
"bunchName": "bunch2",
"size": "10"
},
{
"bunchName": "bunch3",
"size": "5"
}
]
}
]
var findValue = (object, key) => {
var resultValue;
var rec = (currentObj) => {
if(currentObj && typeof currentObj === "object"){
for(let curKey in currentObj){
if (curKey === key){
resultValue = currentObj[curKey];
}else{
rec(currentObj[curKey]);
}
}
}
}
rec(object);
return resultValue;
}
console.log(findValue(object, "bunchName"));

You could add a function that takes an object and a key and returns object[key] and then split your key string into a list of individual keys by the dot. Then you could traverse the list of keys and use the function to get the value for each level in your object:
Totally untested code I just whipped up:
function valueByKey(obj, key) {
if (obj) {
return obj[key];
}
}
function findValue(index, key) {
const keys = key.split('.');
let value = array[index];
for (let i = 0; i < keys.length; i++) {
value = valueByKey(value, keys[i]);
}
return value;
}

Non-recurrent solution:
var array = [
{
'a': {
'b': 1
}
}
];
function findValue(index, key) {
var keys = key.split('.');
var tmp = array[index];
for (var i = 0; i < keys.length; i++) {
if (!tmp.hasOwnProperty(keys[i]) || typeof tmp !== 'object') {
// throw an exception, or return default value – property not found.
}
tmp = tmp[keys[i]];
}
return tmp;
}
findValue(0, 'a.b');

loop through json javascript

I got a json which looks like something like this :
var json = {
"stock1" : {
"positions" : [{
"date": "29/02/2016",
"price": 15,
"type": "short"
}]
},
"stock2" : {
"positions" : [{
"date": "29/02/2016",
"price": 20,
"type": "long"
}]
}
};
For the moment I have something like that :
<script>
function myFunction() {
;
}
</script>
<div id = "short">
<button onclick="myFunction()">
short
</button>
</div>
My json is actually bigger than this example. I'd like to loop through it to get only the positions who are "short" and print them.
What is the best way to do that using only javascript ?
EDIT :
This is my new code but I still can't access to short or long position :
var stocks = [];
var longOnMarket = [];
var shortOnMarket = [];
var typeOfPosition = [];
var lolz = [];
for (var key in json) {
if (json.hasOwnProperty(key)) {
var item = json[key];
lolz.push(JSON.stringify(item));
stocks.push(key);
var json2 = json[item];
for (var key2 in json2) {
if (json2.hasOwnProperty(key2)) {
var longOrShort = json2[key2].positions;
typeOfPosition.push(JSON.stringify(longOrShort));
}
}
}
}
alert(stocks);
alert(lolz);
alert(typeOfPosition);

What you can do is
var json = {
"stock1" : {
"positions" : [{
"date": "29/02/2016",
"price": 15,
"type": "short"
}]
},
"stock2" : {
"positions" : [{
"date": "29/02/2016",
"price": 20,
"type": "long"
}]
}
};
var object = JSON.parse(json);
for (var key in object) {
//Do your stuff
}

This solution looks for the array of positions and returns the object if some short is found.
var object = { "stock1": { "positions": [{ "date": "29/02/2016", "price": 15, "type": "short" }] }, "stock2": { "positions": [{ "date": "29/02/2016", "price": 20, "type": "long" }] } },
short = {};
Object.keys(object).forEach(function (k) {
if (object[k].positions.some(function (a) { return a.type === 'short' })) {
short[k] = object[k];
}
});
document.write('<pre>' + JSON.stringify(short, 0, 4) + '</pre>');

You should simple iterate through your object keys
var result = [];
for (var key in json) {
if (json.hasOwnProperty(key)) {
var item = json[key];
item.positions = item.positions.filter(function(el) { return el.type == 'short' });
result.push(item);
}
}

here is my try please check it out
var i,
shortTypePositionsArray = [],
shortTypeWholeObject = {};
$.each(json,function(key,value){
if(Object.keys(value) == "positions"){
for(i = 0;i<value.positions.length;i++){
if(value.positions[i].type == 'short')
{
shortTypePositionsArray.push(value.positions[i]);
shortTypeWholeObject[key] = value;
}
}
}
});
console.log(shortTypePositionsArray);
console.log(shortTypeWholeObject);

Change key name in nested JSON structure

I have a JSON data structure as shown below:
{
"name": "World",
"children": [
{ "name": "US",
"children": [
{ "name": "CA" },
{ "name": "NJ" }
]
},
{ "name": "INDIA",
"children": [
{ "name": "OR" },
{ "name": "TN" },
{ "name": "AP" }
]
}
]
};
I need to change the key names from "name" & "children" to say "key" & "value". Any suggestion on how to do that for each key name in this nested structure?

I don't know why you have a semicolon at the end of your JSON markup (assuming that's what you've represented in the question), but if that's removed, then you can use a reviver function to make modifications while parsing the data.
var parsed = JSON.parse(myJSONData, function(k, v) {
if (k === "name")
this.key = v;
else if (k === "children")
this.value = v;
else
return v;
});
DEMO: http://jsfiddle.net/BeSad/

Try this:
function convert(data){
return {
key: data.name,
value: data.children.map(convert);
};
}
Or if you need to support older browsers without map:
function convert(data){
var children = [];
for (var i = 0, len = data.children.length; i < len; i++){
children.push(convert(data.children[i]));
}
return {
key: data.name,
value: children
};
}

You could use a function like this :
function clonerename(source) {
if (Object.prototype.toString.call(source) === '[object Array]') {
var clone = [];
for (var i=0; i<source.length; i++) {
clone[i] = goclone(source[i]);
}
return clone;
} else if (typeof(source)=="object") {
var clone = {};
for (var prop in source) {
if (source.hasOwnProperty(prop)) {
var newPropName = prop;
if (prop=='name') newPropName='key';
else if (prop=='children') newPropName='value';
clone[newPropName] = clonerename(source[prop]);
}
}
return clone;
} else {
return source;
}
}
var B = clonerename(A);
Note that what you have isn't a JSON data structure (this doesn't exist as JSON is a data-exchange format) but probably an object you got from a JSON string.