146 lines
4.6 KiB
JavaScript
146 lines
4.6 KiB
JavaScript
function diff(oldArr, newArr, equals) {
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if (!equals) {
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equals = function (a, b) {
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return a === b;
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};
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}
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oldArr = oldArr.slice();
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newArr = newArr.slice();
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var newLen = newArr.length;
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var oldLen = oldArr.length;
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var editLength = 1;
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var maxEditLength = newLen + oldLen;
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var bestPath = [{ newPos: -1, components: [] }];
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var oldPos = extractCommon(bestPath[0], newArr, oldArr, 0, equals);
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if (!oldLen
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|| !newLen
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|| (bestPath[0].newPos + 1 >= newLen && oldPos + 1 >= oldLen)) {
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var indices = [];
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var allCleared = !newLen && oldLen > 0;
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var allCreated = !oldLen && newLen > 0;
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for (var i = 0; i < (allCleared ? oldArr : newArr).length; i++) {
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indices.push(i);
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}
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return [{
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indices: indices,
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count: indices.length,
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added: allCreated,
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removed: allCleared
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}];
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}
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function execEditLength() {
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for (var diagonalPath = -1 * editLength; diagonalPath <= editLength; diagonalPath += 2) {
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var basePath;
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var addPath = bestPath[diagonalPath - 1];
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var removePath = bestPath[diagonalPath + 1];
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var oldPos = (removePath ? removePath.newPos : 0) - diagonalPath;
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if (addPath) {
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bestPath[diagonalPath - 1] = undefined;
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}
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var canAdd = addPath && addPath.newPos + 1 < newLen;
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var canRemove = removePath && 0 <= oldPos && oldPos < oldLen;
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if (!canAdd && !canRemove) {
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bestPath[diagonalPath] = undefined;
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continue;
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}
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if (!canAdd || (canRemove && addPath.newPos < removePath.newPos)) {
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basePath = clonePath(removePath);
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pushComponent(basePath.components, false, true);
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}
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else {
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basePath = addPath;
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basePath.newPos++;
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pushComponent(basePath.components, true, false);
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}
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oldPos = extractCommon(basePath, newArr, oldArr, diagonalPath, equals);
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if (basePath.newPos + 1 >= newLen && oldPos + 1 >= oldLen) {
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return buildValues(basePath.components);
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}
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else {
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bestPath[diagonalPath] = basePath;
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}
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}
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editLength++;
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}
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while (editLength <= maxEditLength) {
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var ret = execEditLength();
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if (ret) {
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return ret;
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}
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}
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}
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function extractCommon(basePath, newArr, oldArr, diagonalPath, equals) {
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var newLen = newArr.length;
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var oldLen = oldArr.length;
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var newPos = basePath.newPos;
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var oldPos = newPos - diagonalPath;
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var commonCount = 0;
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while (newPos + 1 < newLen && oldPos + 1 < oldLen && equals(newArr[newPos + 1], oldArr[oldPos + 1])) {
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newPos++;
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oldPos++;
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commonCount++;
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}
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if (commonCount) {
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basePath.components.push({
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count: commonCount,
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added: false,
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removed: false,
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indices: []
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});
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}
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basePath.newPos = newPos;
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return oldPos;
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}
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function pushComponent(components, added, removed) {
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var last = components[components.length - 1];
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if (last && last.added === added && last.removed === removed) {
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components[components.length - 1] = {
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count: last.count + 1,
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added: added,
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removed: removed,
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indices: []
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};
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}
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else {
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components.push({
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count: 1,
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added: added,
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removed: removed,
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indices: []
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});
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}
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}
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function buildValues(components) {
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var componentPos = 0;
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var componentLen = components.length;
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var newPos = 0;
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var oldPos = 0;
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for (; componentPos < componentLen; componentPos++) {
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var component = components[componentPos];
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if (!component.removed) {
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var indices = [];
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for (var i = newPos; i < newPos + component.count; i++) {
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indices.push(i);
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}
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component.indices = indices;
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newPos += component.count;
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if (!component.added) {
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oldPos += component.count;
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}
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}
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else {
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for (var i = oldPos; i < oldPos + component.count; i++) {
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component.indices.push(i);
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}
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oldPos += component.count;
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}
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}
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return components;
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}
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function clonePath(path) {
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return { newPos: path.newPos, components: path.components.slice(0) };
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}
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export default function arrayDiff(oldArr, newArr, equal) {
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return diff(oldArr, newArr, equal);
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}
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