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const baseTree = { | |
id: 'root', | |
children: [ | |
{ | |
id: 'child0', | |
children: [ | |
{ | |
id: 'child0-0', | |
children: [ | |
{ | |
id: 'child0-0-0', | |
children: [ | |
{ | |
id: 'child0-0-0-0', | |
children: [ | |
{ | |
id: 'child0-0-0-0', | |
children: null, | |
}, | |
], | |
}, | |
], | |
}, | |
{ | |
id: 'child0-0-1', | |
children: null, | |
}, | |
], | |
}, | |
], | |
}, | |
{ | |
id: 'child1', | |
children: [ | |
{ | |
id: 'child1-0', | |
children: null, | |
}, | |
], | |
}, | |
], | |
}; | |
const iterationDfsGetIds = (tree) => { | |
const stack = [tree]; | |
const result = []; | |
while (stack.length > 0) { | |
const { id, children } = stack.pop(); | |
result.push(id); | |
if (children) { | |
stack.push(...children); | |
} | |
} | |
return result; | |
}; | |
/* | |
Don't use this. Really. :) JavaScript does not perform tail recursion optimization, | |
so if your recursion is too deep, you may get a call stack overflow. | |
*/ | |
const recursionDfsGetIds = (tree) => { | |
const result = [tree.id]; | |
if (tree.children) { | |
result.push(...tree.children.map((node) => recursionDfsGetIds(node)).flat()); | |
} | |
return result; | |
}; | |
const iterationBfsGetIds = (tree) => { | |
const queue = [tree]; | |
const result = []; | |
while (queue.length > 0) { | |
const { id, children } = queue.shift(); | |
result.push(id); | |
if (children) { | |
queue.push(...children); | |
} | |
} | |
return result; | |
}; | |
const addParentIds = (tree) => { | |
const newTree = JSON.parse(JSON.stringify(tree)); | |
// root node | |
newTree.parentId = null; | |
const queue = [newTree]; | |
while (queue.length > 0) { | |
const node = queue.shift(); | |
if (node.children) { | |
queue.push( | |
...node.children.map((child) => { | |
// mutating the reference here intentionally | |
child.parentId = node.id; | |
return child; | |
}), | |
); | |
} | |
} | |
return newTree; | |
}; | |
console.log('iterationDfsGetIds', iterationDfsGetIds(baseTree)); | |
console.log('recursionDfsGetIds', recursionDfsGetIds(baseTree)); | |
console.log('iterationBfsGetIds', iterationBfsGetIds(baseTree)); | |
console.log('addParentIds', JSON.stringify(addParentIds(baseTree), null, 2)); |
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