如何从ejs数组中的所有对象获取所有使用的值

Question

Let's say I have an array, which contains "image" objects. Inside an "image" I have another array, called "tags". I have this to sort images. However, I do not know how to get all values in all "tags" arrays, without getting duplicates.

Here's an overview of two "image" objects and the data I want to get.

{
"image1": { //IMAGE OBJECT 1
"path": "/res/img/path",
"name": "Red Car",
"tags": ["Red", "Cars"] //I want both of these values.
},
"image2": { //IMAGE OBJECT 2
    "path": "/res/img/otherpath",
    "name": "Blue Car",
    "tags": ["Blue", "Cars"] //I only want the 'Blue' tag, because 'Cars' would be duplicate.
},
"image3": { //IMAGE OBJECT 3
    "path": "/res/img/otherotherpath",
    "name": "Red Fridge",
    "tags": ["Red", "Fridge"] //I only want the 'Fridge' tag, because 'Red' would be duplicate.
}

Does anyone know how to do this? I do not need exact code, just the concept. I wanna figure out the code myself :)

Answer 1

You can make use of array.map() in combination with array.reduce() .

console.log(
  array
    .map(obj => obj.tags) // get all tags
    .flat() // and convert it to one big list
    .reduce((arr, val) => arr.includes(val) ? arr : arr.concat(val), []) // remove duplicates
);

Answer 2

Try this,

var data = {
"image1": { //IMAGE OBJECT 1
"path": "/res/img/path",
"name": "Red Car",
"tags": ["Red", "Cars"] //I want both of these values.
},
"image2": { //IMAGE OBJECT 2
    "path": "/res/img/otherpath",
    "name": "Blue Car",
    "tags": ["Blue", "Cars"] //I only want the 'Blue' tag, because 'Cars' would be duplicate.
},
"image3": { //IMAGE OBJECT 3
    "path": "/res/img/otherotherpath",
    "name": "Red Fridge",
    "tags": ["Red", "Fridge"] //I only want the 'Fridge' tag, because 'Red' would be duplicate.
}
}
var filteredArray = new Set();

Object.keys(data).forEach((key) => {
    data[key]['tags'].forEach((tag) => {
    filteredArray.add(tag)
  })
});
filteredArray = Array.from(filteredArray).sort();
console.log(filteredArray);

Answer 3

 const colors = ['red', 'green', 'green', 'red', 'blue', 'red', 'blue']
 
 function copyArrayWithNoDupes(array) {
  return Array.from(new Set([...array])).sort();
}
console.log(copyArrayWithNoDupes(colors))

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/set

Answer 4

I hope this code helping you

var obj = {
"image1": { //IMAGE OBJECT 1
"path": "/res/img/path",
"name": "Red Car",
"tags": ["Red", "Cars"] //I want both of these values.
},
"image2": { //IMAGE OBJECT 2
    "path": "/res/img/otherpath",
    "name": "Blue Car",
    "tags": ["Blue", "Cars"] //I only want the 'Blue' tag, because 'Cars' would be duplicate.
},
"image3": { //IMAGE OBJECT 3
    "path": "/res/img/otherotherpath",
    "name": "Red Fridge",
    "tags": ["Red", "Fridge"] //I only want the 'Fridge' tag, because 'Red' would be duplicate.
}
}
Object.values(obj).flatMap(o=>o.tags).filter((elem, index, self)=>index === self.indexOf(elem))

Answer 5

Use Object.keys

 var tags = { "image1": { //IMAGE OBJECT 1 "path": "/res/img/path", "name": "Red Car", "tags": ["Red", "Cars"] //I want both of these values. }, "image2": { //IMAGE OBJECT 2 "path": "/res/img/otherpath", "name": "Blue Car", "tags": ["Blue", "Cars"] //I only want the 'Blue' tag, because 'Cars' would be duplicate. }, "image3": { //IMAGE OBJECT 3 "path": "/res/img/otherotherpath", "name": "Red Fridge", "tags": ["Red", "Fridge"] //I only want the 'Fridge' tag, because 'Red' would be duplicate. } } var filteredTags = new Set(); Object.keys(tags).forEach((key) => { tags[key]['tags'].forEach((tag) => { filteredTags.add(tag) }) }); filteredTags = Array.from(filteredTags).sort(); console.log(filteredTags);