Remove duplicates from array in typescript

user_11542297 0
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I am new to typescript, and i've been having some problems in using my javascript skills. For example, can someone help me to write this exactly same javascript code below in typescript?

If not possible at all, any typescript function that will render the expected output (array without duplicate values).

This is just a simple way to remove duplicates from an array, but seems like typescript doesn't let me define an empty object... I'm not sure...

The output of the code below is: ['John', 'Paul', 'George', 'Ringo']

Thanks!

const names = ['John', 'Paul', 'George', 'Ringo', 'John'];

function removeDups(names) {
  let unique = {};
  names.forEach(function(i) {
    if(!unique[i]) {
      unique[i] = true;
    }
  });
  return Object.keys(unique);
}

removeDups(names)
typescript ecmascript-6 javascript
2 Answers

In this case, you just have to add types

const names = ['John', 'Paul', 'George', 'Ringo', 'John'];

function removeDups(names: string[]) {
  let unique: any = {};
  names.forEach(function(i: string) {
    if(!unique[i]) {
      unique[i] = true;
    }
  });
  return Object.keys(unique);
}

removeDups(names)

typescript playground

user_66551600 
names = ['John', 'Paul', 'George', 'Ringo', 'John']; 

removeDups(names) {
 let unique = {};
  this.names.forEach((i) => {
    if(!unique[i]) {
      unique[i] = true;
    }
  });
  return Object.keys(unique);
}

Then call removeDups from where you want

Here is another way:

names = ['John', 'Paul', 'George', 'Ringo', 'John']; 

removeDups(names) {

  return this.names.filter((elem, index, self)=> {
    return index === self.indexOf(elem);
})
}
user_19303480
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