exports = function(edges) {
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return sort(uniqueNodes(edges), edges);
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};
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function uniqueNodes(arr) {
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var ret = [];
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for (var i = 0, len = arr.length; i < len; i++) {
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var edge = arr[i];
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if (ret.indexOf(edge[0]) < 0) ret.push(edge[0]);
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if (ret.indexOf(edge[1]) < 0) ret.push(edge[1]);
|
}
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return ret;
|
}
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function sort(nodes, edges) {
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var cursor = nodes.length;
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var sorted = new Array(cursor);
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var visited = {};
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var i = cursor;
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while (i--) {
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if (!visited[i]) visit(nodes[i], i, []);
|
}
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function visit(node, i, predecessors) {
|
if (predecessors.indexOf(node) >= 0) {
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throw new Error('Cyclic dependency: ' + JSON.stringify(node));
|
}
|
if (visited[i]) return;
|
visited[i] = true;
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var outgoing = edges.filter(function(edge) {
|
return edge[0] === node;
|
});
|
|
if ((i = outgoing.length)) {
|
var preds = predecessors.concat(node);
|
do {
|
var child = outgoing[--i][1];
|
visit(child, nodes.indexOf(child), preds);
|
} while (i);
|
}
|
sorted[--cursor] = node;
|
}
|
return sorted;
|
}
|
|
module.exports = exports;
|
