Question 194238 in Javascript Question posted in
A very good W3school tutorial can be found here.

Javascript – How can I extract duplicates from an array using ExtendScript?

I am trying to identify duplicate object names in an Illustrator file using ExtendScript so I can group them. I can get an array of all PageItems on a layer, I just don’t know how to identify and store duplicates so I can perform the group operation.

This is a rather pathetic attempt at doing what I want:

var aLayer = app.activeDocument.activeLayer;
var pageItemsRef = aLayer.pageItems;
var duplicateNames = [];
var currentName;

for (var i = 0, len = pageItemsRef.length; i < len; i++) {
    if(i==0){
        currentName = pageItemsRef[0].name;
        continue;
    }
    if(pageItemsRef[i].name == currentName){
        var ref = {name:pageItemsRef[i].name, index:i}
        duplicateNames.push(ref);
    }
}

Continuing with this code will only give me consecutive duplicates. Sorry for the low quality example but I just don’t know where to start.

I just want to iterate pageItemsRef and store the name + ID into separate arrays.

So array [0] will have 2+ duplicates stored as objects (Name, ID)
Array [1] might have 5+ duplicates stored as objects also stored as (Name,ID)
etc.

Any more efficient approaches are warmly welcomed as well. I am new to ExtendScript.

Any help greatly appreciated.

Tags:

3

Answers


  1. 0

    You can use reduce method to find duplicate,

    const duplicates = pageItemsRef.reduce((current,data,index)=>{
  current[data.name] ??= [];
  current[data.name].push({
     name:data.name,
     index
  });
  return current;
},{});
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  2. 0

    Try This"

    var aLayer = app.activeDocument.activeLayer;
var pageItemsRef = aLayer.pageItems;
var duplicates = {};

for (var i = 0, len = pageItemsRef.length; i < len; i++) {
    var currentItemName = pageItemsRef[i].name;
    if (duplicates[currentItemName] == null) {
        duplicates[currentItemName] = [];
    }
    duplicates[currentItemName].push({name: currentItemName, index: i});
}
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  3. 0

    You can count the number of times that each targeted property value appears, then filter the array based on whether the count is greater than 1:

    TS Playground

    function findDuplicates<T, K>(
  array: readonly T[],
  selector: (element: T) => K,
): T[] {
  const counts = new Map<K, number>();

  for (const element of array) {
    const key = selector(element);
    counts.set(key, (counts.get(key) ?? 0) + 1);
  }

  return array.filter(element => counts.get(selector(element))! > 1);
}

/**
 * The type of a PageItem object — which apparently already has an ID:
 * - https://ai-scripting.docsforadobe.dev/jsobjref/PageItem.html#pageitem-uuid
 * - https://github.com/aenhancers/Types-for-Adobe/issues/64
 */
type PageItem = {
  name: string;
  readonly uuid: string;
  // etc.
};

// I can't validate that the structure you presented in the question is accurate,
// but here's a concrete example of that:
const app = {
  activeDocument: {
    activeLayer: {
      pageItems: [
        "a", // dup
        "b",
        "c", // dup
        "a", // dup
        "c", // dup
        "d",
        "a", // dup
        "f",
      ].map(name => ({
        name,
        uuid: window.crypto.randomUUID(),
      })),
    },
  },
} satisfies { activeDocument: { activeLayer: { pageItems: readonly PageItem[] } } };


// Get only the duplicates like this:
const result = findDuplicates(
  app.activeDocument.activeLayer.pageItems,
  (pageItem) => pageItem.name,
);

console.log(result); // The objects at indexes 0, 2, 3, 4, 6

const expected = app.activeDocument.activeLayer.pageItems.filter(
  (_, i) => [0, 2, 3, 4, 6].includes(i),
);

console.log(JSON.stringify(result) === JSON.stringify(expected)); // true

    Compiled JS from the playground link above:

    "use strict";
function findDuplicates(array, selector) {
    const counts = new Map();
    for (const element of array) {
        const key = selector(element);
        counts.set(key, (counts.get(key) ?? 0) + 1);
    }
    return array.filter(element => counts.get(selector(element)) > 1);
}
const app = {
    activeDocument: {
        activeLayer: {
            pageItems: [
                "a",
                "b",
                "c",
                "a",
                "c",
                "d",
                "a",
                "f",
            ].map(name => ({
                name,
                uuid: window.crypto.randomUUID(),
            })),
        },
    },
};
const result = findDuplicates(app.activeDocument.activeLayer.pageItems, (pageItem) => pageItem.name);
console.log(result);
const expected = app.activeDocument.activeLayer.pageItems.filter((_, i) => [0, 2, 3, 4, 6].includes(i));
console.log(JSON.stringify(result) === JSON.stringify(expected));
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