javascript - How to get the total depth of an unknown JSON hierarchy? -


i've been struggling find/build recursive function parse json file , total depth of children.

the file looks this:

var input = {     "name": "positive",     "children": [{         "name": "product service",         "children": [{             "name": "price",             "children": [{                 "name": "cost",                 "size": 8             }]         }, {             "name": "quality",             "children": [{                 "name": "messaging",                 "size": 4             }]         }]     }, {         "name": "customer service",         "children": [{             "name": "personnel",             "children": [{                 "name": "ceo",                 "size": 7             }]         }]     }, {         "name": "product",         "children": [{             "name": "apple",             "children": [{                 "name": "iphone 4",                 "size": 10             }]         }]     }]  }

you can use recursive function go through whole tree: 

getdepth = function (obj) {     var depth = 0;     if (obj.children) {         obj.children.foreach(function (d) {             var tmpdepth = getdepth(d)             if (tmpdepth > depth) {                 depth = tmpdepth             }         })     }     return 1 + depth }

the function works follow:

  • if object not leaf (i.e object has children attribute), then:
    • compute depth of each child, save maximal one
    • return 1 + depth of deepest child
  • otherwise, return 1

jsfiddle: http://jsfiddle.net/chrisjamesc/hftn8/

edit modern javascript, function this: 

const getdepth = ({ children }) => 1 +     (children ? math.max(...children.map(getdepth)) : 0)

jsfiddle: http://jsfiddle.net/chrisjamesc/hftn8/59/


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