| 1 | /**
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| 2 | * generates a UID factory
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| 3 | * @internal
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| 4 | * @example
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| 5 | * const uid = generateUID();
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| 6 | * uid(object) = 1;
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| 7 | * uid(object) = 1;
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| 8 | * uid(anotherObject) = 2;
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| 9 | */
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| 10 | export const generateUID = () => {
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| 11 | let counter = 1;
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| 12 | const map = new WeakMap();
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| 13 | /**
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| 14 | * @borrows {uid}
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| 15 | */
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| 16 | const uid = (item, index) => {
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| 17 | if (typeof item === 'number' || typeof item === 'string') {
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| 18 | return index ? `idx-${index}` : `val-${item}`;
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| 19 | }
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| 20 | if (!map.has(item)) {
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| 21 | map.set(item, counter++);
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| 22 | return uid(item);
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| 23 | }
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| 24 | return 'uid' + map.get(item);
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| 25 | };
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| 26 | return uid;
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| 27 | };
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| 28 | /**
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| 29 | * @name uid
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| 30 | * returns an UID associated with {item}
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| 31 | * @param {Object} item - object to generate UID for
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| 32 | * @param {Number} index, a fallback index
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| 33 | * @example
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| 34 | * uid(object) == 1;
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| 35 | * uid(object) == 1;
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| 36 | * uid(anotherObject) == 2;
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| 37 | * uid("not object", 42) == 42
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| 38 | *
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| 39 | * @see {@link useUID}
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| 40 | */
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| 41 | export const uid = generateUID();
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