How to remove all duplicates from an array of objects?

How about with some es6 magic?

things.thing = things.thing.filter((thing, index, self) =>  index === self.findIndex((t) => (    t.place === thing.place && t.name === thing.name  )))

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A more generic solution would be:

const uniqueArray = things.thing.filter((thing, index) => {  const _thing = JSON.stringify(thing);  return index === things.thing.findIndex(obj => {    return JSON.stringify(obj) === _thing;  });});

Using the above property strategy instead of JSON.stringify:

const isPropValuesEqual = (subject, target, propNames) =>  propNames.every(propName => subject[propName] === target[propName]);const getUniqueItemsByProperties = (items, propNames) =>   items.filter((item, index, array) =>    index === array.findIndex(foundItem => isPropValuesEqual(foundItem, item, propNames))  );

You can add a wrapper if you want the propNames property to be either an array or a value:

const getUniqueItemsByProperties = (items, propNames) => {  const propNamesArray = Array.from(propNames);  return items.filter((item, index, array) =>    index === array.findIndex(foundItem => isPropValuesEqual(foundItem, item, propNamesArray))  );};

allowing both getUniqueItemsByProperties('a') and getUniqueItemsByProperties(['a']);

Stackblitz Example

Explanation

• Start by understanding the two methods used:
  • filter, findIndex
• Next take your idea of what makes your two objects equal and keep that in mind.
• We can detect something as a duplicate, if it satisfies the criterion that we have just thought of, but it's position is not at the first instance of an object with the criterion.
• Therefore we can use the above criterion to determine if something is a duplicate.

Shortest one liners for ES6+

Find unique id's in an array.

arr.filter((v,i,a)=>a.findIndex(t=>(t.id === v.id))===i)

Unique by multiple properties ( place and name )

arr.filter((v,i,a)=>a.findIndex(t=>(t.place === v.place && t.name===v.name))===i)

Unique by all properties (This will be slow for large arrays)

arr.filter((v,i,a)=>a.findIndex(t=>(JSON.stringify(t) === JSON.stringify(v)))===i)

Keep the last occurrence.

arr.slice().reverse().filter((v,i,a)=>a.findIndex(t=>(t.id === v.id))===i).reverse()

A primitive method would be:

var obj = {};for ( var i=0, len=things.thing.length; i < len; i++ )    obj[things.thing[i]['place']] = things.thing[i];things.thing = new Array();for ( var key in obj )    things.thing.push(obj[key]);