1 | /**
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2 | * SetArray acts like a `Set` (allowing only one occurrence of a string `key`), but provides the
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3 | * index of the `key` in the backing array.
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4 | *
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5 | * This is designed to allow synchronizing a second array with the contents of the backing array,
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6 | * like how in a sourcemap `sourcesContent[i]` is the source content associated with `source[i]`,
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7 | * and there are never duplicates.
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8 | */
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9 | class SetArray {
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10 | constructor() {
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11 | this._indexes = { __proto__: null };
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12 | this.array = [];
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13 | }
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14 | }
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15 | /**
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16 | * Typescript doesn't allow friend access to private fields, so this just casts the set into a type
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17 | * with public access modifiers.
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18 | */
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19 | function cast(set) {
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20 | return set;
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21 | }
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22 | /**
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23 | * Gets the index associated with `key` in the backing array, if it is already present.
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24 | */
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25 | function get(setarr, key) {
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26 | return cast(setarr)._indexes[key];
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27 | }
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28 | /**
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29 | * Puts `key` into the backing array, if it is not already present. Returns
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30 | * the index of the `key` in the backing array.
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31 | */
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32 | function put(setarr, key) {
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33 | // The key may or may not be present. If it is present, it's a number.
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34 | const index = get(setarr, key);
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35 | if (index !== undefined)
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36 | return index;
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37 | const { array, _indexes: indexes } = cast(setarr);
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38 | const length = array.push(key);
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39 | return (indexes[key] = length - 1);
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40 | }
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41 | /**
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42 | * Pops the last added item out of the SetArray.
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43 | */
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44 | function pop(setarr) {
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45 | const { array, _indexes: indexes } = cast(setarr);
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46 | if (array.length === 0)
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47 | return;
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48 | const last = array.pop();
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49 | indexes[last] = undefined;
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50 | }
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51 | /**
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52 | * Removes the key, if it exists in the set.
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53 | */
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54 | function remove(setarr, key) {
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55 | const index = get(setarr, key);
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56 | if (index === undefined)
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57 | return;
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58 | const { array, _indexes: indexes } = cast(setarr);
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59 | for (let i = index + 1; i < array.length; i++) {
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60 | const k = array[i];
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61 | array[i - 1] = k;
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62 | indexes[k]--;
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63 | }
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64 | indexes[key] = undefined;
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65 | array.pop();
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66 | }
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67 |
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68 | export { SetArray, get, pop, put, remove };
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69 | //# sourceMappingURL=set-array.mjs.map
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