cute graph-traversal
npm install grad-school
**grad-school** is a tool for creating ad-hoc graphs, in a scripting language, and then querying them.
it's surprising how there's no super-clear way to author graph-data, or even think about.
It always hurts my head. Even simple graphs do.
Maybe i have a head-problem, or maybe JSON is just an awkward way to represent graphs.
either way...
library is like, 3kb.
---
### Ok, graphs -
we support 3 formats:
### String-format
this is a pretty-flexible way to declare a graph, using indents and `->` syntax. It's harder to add metadata to nodes.
It's a bit like how graphviz does it:
```js
let str = `
a -> a2 -> a21
-> a1
b
`
let g = grad(str).debug()
g.nodes().length // 5
```
### flat json:
this flat, parent-indexed json is easy to make, but the graph is harder to 'see':
```js
let nodes = [
{ id: 'a', parent: null },
{ id: 'b', parent: null },
{ id: 'a1', parent: 'a' },
{ id: 'a2', parent: 'a' },
{ id: 'a21', parent: 'a2' },
]
let g = grad(str).debug()
/*
→ a
→ a2
→ a21
→ a1
→ b
*/
```
### nested json:
this is how d3 does it:
```js
let nodes = {
children: [
{
id: 'a',
children: [{ id: 'a1' }, { id: 'a2', children: [{ id: 'a21' }] }],
},
{ id: 'b' },
],
}
let g = grad(str).debug()
/*
→ a
→ a2
→ a21
→ a1
→ b
*/
```
## JS API
you can also easily mess-around with the graph:
```js
let g = grad('a -> a1')
// add new nodes
g.add('b').add(['b1', 'b2'])
g.add('c')
// get a node by a json-pointer
g.get('/b/b1').remove()
console.log(g.get('b').children)
console.log(g.out())
```
## Fill-down
you can 'deduce', down the tree, and intellegently merge the properties of each node:
```js
let str = `
a
b -> b1
c -> c1 -> c2
`
let g = grad(str)
// add some data to one node
g.get('c').props({ inC: true })
g.fillDown()
// check a c-leaf
g.get('c/c1/c2').json.props
// { inC: true }
g.get('b').json.props
// {}
```
it will concat arrays, merge objects and sets:
```js
let str = `
a -> a1 -> a11
b -> b1
`
let g = grad(str)
// add data to root
g.props({ list: ['fromRoot'] })
// add data to child
g.get('a').props({ list: ['fromA'] })
g.fillDown()
// b-side has root-data
let have = g.get('b/b1').json.props
// { list: ['fromRoot'] }
// a-side has merged arrays
let have = g.get('a/a1/a11').json.props
// { list: ['fromRoot','fromA'] }
```
MIT