Getting array of school values from all objects using JS-CodePudding

Hello I am new to the JavaScript language.

I have a table1.data property that's an array of objects with data about a school like:

{ schoolName: "School 1", telephone: "123456", address: "1st street, 1st road" }

Can I perhaps get an array of the telephone values from all the objects using JS? Please help.

CodePudding user response：

All you need to do it traverse the items in the data, while grabbing the telephone field value.

Here is the long-way:

const table1 = {
  data: [
    { schoolName: "School 1", telephone: "(111) 111-1111", address: "1st street" },
    { schoolName: "School 2", telephone: "(222) 222-2222", address: "2nd street" },
    { schoolName: "School 3", telephone: "(333) 333-3333", address: "3rd street" }
  ]
};

const phoneNumbers = [];
for (let i = 0; i < table1.data.length; i  ) {
  phoneNumbers.push(table1.data[i].telephone);
}

console.log(phoneNumbers);

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Here is the short way:

const table1 = {
  data: [
    { schoolName: "School 1", telephone: "(111) 111-1111", address: "1st street" },
    { schoolName: "School 2", telephone: "(222) 222-2222", address: "2nd street" },
    { schoolName: "School 3", telephone: "(333) 333-3333", address: "3rd street" }
  ]
};

const phoneNumbers = table1.data.map(({ telephone }) => telephone);

console.log(phoneNumbers);

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CodePudding user response：

Why not use a for loop

let data = [
  {schoolName: "School 1", telephone: "123456", address: "1st street, 1st road"},
  {schoolName: "School 2", telephone: "654321", address: "2nd street, 2nd road"}
];

let telephoneArr = [];
for (const addressObj of data) {
   telephoneArr.push(addressObj.telephone);
};
console.log(telephoneArr);

Or you could use Object.keys

let data = [
  {schoolName: "School 1", telephone: "123456", address: "1st street, 1st road"},
  {schoolName: "School 2", telephone: "654321", address: "2nd street, 2nd road"}
];

let telephoneArr = [];
data.forEach(school => Object.keys(school).forEach(function(key, index) {
  if (key === 'telephone') telephoneArr.push(school[key]);
}));

console.log(telephoneArr);

CodePudding user response：

You can use the javascript map function which creates a new array by calling a function for every array element.

let table1 = [{ schoolName: "School 1", telephone: "123456", address: "1st street, 1st road" },
{ schoolName: "School 2", telephone: "654321", address: "2nd street, 2nd road" },
{ schoolName: "School 1", telephone: "321654", address: "3rd street, 3rd road" }];

//new empty array that will hold th phone numbers
const phoneNumbers = [];

table1.map(({telephone})=>{
//populate the phoneNumbers array with phone numbers by iterating the initial array
phoneNumbers.push(telephone)
})

console.log(phoneNumbers)