Paths & metrics

Import as import * as t from 'neotraverse'.

findPaths · filterPaths

Return where a match occurred, not only the value. t.findPaths stops at the first hit; t.filterPaths returns { path, node }[].

Example

import * as t from 'neotraverse';

const tree = { users: [{ id: 1 }, { id: 2, flag: true }] };

t.findPaths(tree, (_, x) => x === true); // ['users', '1', 'flag']
t.filterPaths(tree, (ctx) => ctx.isLeaf && typeof ctx.node === 'number');
// → [{ path: ['users','0','id'], node: 1 }, …]

getPath · setPath · hasPath

String paths over array get / set / has. Dot notation (a.b.0) or JSON Pointer (/a/b/0). Unsafe segments (__proto__, etc.) throw at parse time.

Example

import * as t from 'neotraverse';

const config = { server: { host: 'localhost', port: 3000 } };

t.getPath(config, 'server.port'); // 3000
t.setPath(config, 'server.port', 8080);
t.hasPath(config, 'server.tls'); // false

// JSON Pointer (leading slash)
t.getPath(config, '/server/host'); // 'localhost' after set

count · size

t.size(obj) counts every visited node. t.count(obj, fn) counts nodes where the predicate is true.

Example

import * as t from 'neotraverse';

const tree = { a: 1, b: { c: 2 } };
t.size(tree); // 4 (root + a + b + c)
t.count(tree, (_, x) => x === 2); // 1

getType

t.getType(value) returns a stable tag for branching inside callbacks. See Types and traversal for the full matrix.

select

Glob path query: *, key[*], dot segments. For predicate search, use t.filterPaths.

Example

import * as t from 'neotraverse';

const data = { users: [{ email: 'a@x.com' }, { email: 'b@x.com' }] };

t.select(data, 'users[*].email');
// → [{ path: ['users','0','email'], node: 'a@x.com' }, …]