Recursively loop through objects of object

Question

I'm trying to write a recursive function to go through an object and return items based off an ID. I can get the first part of this to work, but I'm having a hard time trying to get this function in a recursive manner and could use a fresh set of eyes. The code is below. When you run the snippet, you get an array of 6 items which for the first iteration is what I want, but how can I call my function with the proper parameters to get the nested items? My end goal is to have the all the objects starting with 'Cstm', nested ones too, to be added to the tablesAndValues array. I was trying to model my code after this: Get all key values from multi level nested array JavaScript, but this deals with an array of objects and not an object of objects. Any hint or tips I can get are very appreciated.

JSFiddle: https://jsfiddle.net/xov49jLs/

const response = {
  "data": {
    "Cstm_PF_ADG_URT_Disposition": {
      "child_welfare_placement_value": ""
    },
    "Cstm_PF_ADG_URT_Demographics": {
      "school_grade": "family setting",
      "school_grade_code": ""
    },
    "Cstm_Precert_Medical_Current_Meds": [
      {
        "med_name": "med1",
        "dosage": "10mg",
        "frequency": "daily"
      },
      {
        "med_name": "med2",
        "dosage": "20mg",
        "frequency": "daily"
      }
    ],
    "Cstm_PF_ADG_URT_Substance_Use": {
      "dimension1_comment": "dimension 1 - tab1",
      "Textbox1": "text - tab1"
    },
    "Cstm_PF_ADG_Discharge_Note": {
      "prior_auth_no_comm": "auth no - tab2"
    },
    "Cstm_PF_ADG_URT_Clinical_Plan": {
      "cca_cs_dhs_details": "details - tab2"
    },
    "container": {
      "Cstm_PF_Name": {
        "first_name": "same text for textbox - footer",
        "last_name": "second textbox - footer"
      },
      "Cstm_PF_ADG_URT_Demographics": {
        "new_field": "mapped demo - footer"
      },
      "grid2": [
        {
          "Cstm_PF_ADG_COMP_Diagnosis": {
            "diagnosis_label": "knee",
            "diagnosis_group_code": "leg"
          }
        },
        {
          "Cstm_PF_ADG_COMP_Diagnosis": {
            "diagnosis_label": "ankle",
            "diagnosis_group_code": "leg"
          }
        }
      ]
    },
    "submit": true
  }
};

function getNamesAndValues(data, id) {
  const tablesAndValues = [],
        res = data;
 
  Object.entries(res).map(([key, value]) => {
    const newKey = key.split('_')[0].toLowerCase();
    
    // console.log(newKey) // -> 'cstm'
    
    if (newKey === id) {
      tablesAndValues.push({
        table: key,
        values: value
      });
    } else {
      // I can log value and key and see what I want to push 
      // to the tablesAndValues array, but I can't seem to get 
      // how to push the nested items.
      
      // console.log(value);
      // console.log(key);
      
      // getNamesAndValues(value, key)
    }
  });
  
  return tablesAndValues;
}

console.log(getNamesAndValues(response.data, 'cstm'));

Answer 1

A reasonably elegant recursive answer might look like this:

const getNamesAndValues = (obj) => 
  Object (obj) === obj
    ? Object .entries (obj)
        .flatMap (([k, v]) => [
          ... (k .toLowerCase () .startsWith ('cstm') ? [{table: k, value: v}] : []), 
          ... getNamesAndValues (v)
        ])
    : []

const response = {data: {Cstm_PF_ADG_URT_Disposition: {child_welfare_placement_value: ""}, Cstm_PF_ADG_URT_Demographics: {school_grade: "family setting", school_grade_code: ""}, Cstm_Precert_Medical_Current_Meds: [{med_name: "med1", dosage: "10mg", frequency: "daily"}, {med_name: "med2", dosage: "20mg", frequency: "daily"}], Cstm_PF_ADG_URT_Substance_Use: {dimension1_comment: "dimension 1 - tab1", Textbox1: "text - tab1"}, Cstm_PF_ADG_Discharge_Note: {prior_auth_no_comm: "auth no - tab2"}, Cstm_PF_ADG_URT_Clinical_Plan: {cca_cs_dhs_details: "details - tab2"}, container: {Cstm_PF_Name: {first_name: "same text for textbox - footer", last_name: "second textbox - footer"}, Cstm_PF_ADG_URT_Demographics: {new_field: "mapped demo - footer"}, grid2: [{Cstm_PF_ADG_COMP_Diagnosis: {diagnosis_label: "knee", diagnosis_group_code: "leg"}}, {Cstm_PF_ADG_COMP_Diagnosis: {diagnosis_label: "ankle", diagnosis_group_code: "leg"}}]}, submit: true}}

console .log (getNamesAndValues (response))

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But this is not as simple as I would like. This code mixes the searching for matches and the test used in that searching together with the formatting of the output. It means that it is a custom function that is both more complex to understand and less reusable than I would like.

I would prefer to use some reusable functions, separating out three feature of this functionality. So, while the following involves more lines of code, I think it makes more sense:

const findAllDeep = (pred) => (obj) => 
  Object (obj) === obj
    ? Object .entries (obj)
        .flatMap (([k, v]) => [
          ... (pred (k, v) ? [[k, v]] : []), 
          ... findAllDeep (pred) (v)
        ])
    : []

const makeSimpleObject = (name1, name2) => ([k, v]) => 
 ({[name1]: k, [name2]: v})

const makeSimpleObjects = (name1, name2) => (xs) => 
  xs .map (makeSimpleObject (name1, name2))

const cstmTest = k => 
  k .toLowerCase () .startsWith ('cstm')

const getNamesAndValues = (obj) => 
  makeSimpleObjects ('table', 'values') (findAllDeep (cstmTest) (obj))

const response = {data: {Cstm_PF_ADG_URT_Disposition: {child_welfare_placement_value: ""}, Cstm_PF_ADG_URT_Demographics: {school_grade: "family setting", school_grade_code: ""}, Cstm_Precert_Medical_Current_Meds: [{med_name: "med1", dosage: "10mg", frequency: "daily"}, {med_name: "med2", dosage: "20mg", frequency: "daily"}], Cstm_PF_ADG_URT_Substance_Use: {dimension1_comment: "dimension 1 - tab1", Textbox1: "text - tab1"}, Cstm_PF_ADG_Discharge_Note: {prior_auth_no_comm: "auth no - tab2"}, Cstm_PF_ADG_URT_Clinical_Plan: {cca_cs_dhs_details: "details - tab2"}, container: {Cstm_PF_Name: {first_name: "same text for textbox - footer", last_name: "second textbox - footer"}, Cstm_PF_ADG_URT_Demographics: {new_field: "mapped demo - footer"}, grid2: [{Cstm_PF_ADG_COMP_Diagnosis: {diagnosis_label: "knee", diagnosis_group_code: "leg"}}, {Cstm_PF_ADG_COMP_Diagnosis: {diagnosis_label: "ankle", diagnosis_group_code: "leg"}}]}, submit: true}}

console .log (findAllDeep (cstmTest) (response))

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These are all helper functions of varying degree of reusability:

• makeSimpleObject takes two key names, say 'foo', and 'bar' and returns a function which takes a two-element array, say [10, 20] and returns an object matching those up, like {foo: 10, bar: 20}

• makeSimpleObjects does the same thing for an array of two-element arrays: makeSimpleObjects('foo', 'bar')([[8, 6], [7, 5], [30, 9]]) //=> [{foo: 8, bar: 6}, {foo: 7, bar: 5}, {foo: 30, bar: 9}].

• cstmTest is a simple predicate to test whether a key begins (case-insensitively) with "cstm".

• and findAllDeep takes a predicate and returns a function which takes an object and returns an array of two-element arrays, holding the keys/value pairs for any items which match the predicate. (The predicate is supplied both the key and the value; in the current case we only need the key, but it seems sensible for the function to take either.

Our main function, getNamesAndValues, uses findAllDeep (cstmTest) to find the matching values and then makeSimpleObjects ('table', 'values') to convert the result to the final format.

Note that findAllDeep, makeSimpleObject, and makeSimpleObjects are all functions likely to be useful elsewhere. The customization here is only in cstmTest and in the short definition for getNamesAndValues. I would count that as a win.

Answer 2

Here's another approach using generators -

const keySearch = (t = [], q = "") =>
  filter(t, ([ k, _ ]) => String(k).startsWith(q))

const r = 
  Array.from
    ( keySearch(response, "Cstm")
    , ([ table, values ]) =>
        ({ table, values })
    )

console.log(r)

[
  {
    table: 'Cstm_PF_ADG_URT_Disposition',
    values: { child_welfare_placement_value: '' }
  },
  {
    table: 'Cstm_PF_ADG_URT_Demographics',
    values: { school_grade: 'family setting', school_grade_code: '' }
  },
  {
    table: 'Cstm_Precert_Medical_Current_Meds',
    values: [ [Object], [Object] ]
  },
  {
    table: 'Cstm_PF_ADG_URT_Substance_Use',
    values: {
      dimension1_comment: 'dimension 1 - tab1',
      Textbox1: 'text - tab1'
    }
  },
  {
    table: 'Cstm_PF_ADG_Discharge_Note',
    values: { prior_auth_no_comm: 'auth no - tab2' }
  },
  {
    table: 'Cstm_PF_ADG_URT_Clinical_Plan',
    values: { cca_cs_dhs_details: 'details - tab2' }
  },
  {
    table: 'Cstm_PF_Name',
    values: {
      first_name: 'same text for textbox - footer',
      last_name: 'second textbox - footer'
    }
  },
  {
    table: 'Cstm_PF_ADG_URT_Demographics',
    values: { new_field: 'mapped demo - footer' }
  },
  {
    table: 'Cstm_PF_ADG_COMP_Diagnosis',
    values: { diagnosis_label: 'knee', diagnosis_group_code: 'leg' }
  },
  {
    table: 'Cstm_PF_ADG_COMP_Diagnosis',
    values: { diagnosis_label: 'ankle', diagnosis_group_code: 'leg' }
  }
]

Above, keySearch is simply a specialisation of filter -

function* filter (t = [], test = v => v)
{ for (const v of traverse(t)){
    if (test(v))
      yield v
  }
}

Which is a specialisation of traverse -

function* traverse (t = {})
{ if (Object(t) === t)
    for (const [ k, v ] of Object.entries(t))
      ( yield [ k, v ]
      , yield* traverse(v)
      )
}

Expand the snippet below to verify the result in your browser -

function* traverse (t = {})
{ if (Object(t) === t)
    for (const [ k, v ] of Object.entries(t))
      ( yield [ k, v ]
      , yield* traverse(v)
      )
}

function* filter (t = [], test = v => v)
{ for (const v of traverse(t)){
    if (test(v))
      yield v
  }
}

const keySearch = (t = [], q = "") =>
  filter(t, ([ k, _ ]) => String(k).startsWith(q))

const response =
  {"data":{"Cstm_PF_ADG_URT_Disposition":{"child_welfare_placement_value":""},"Cstm_PF_ADG_URT_Demographics":{"school_grade":"family setting","school_grade_code":""},"Cstm_Precert_Medical_Current_Meds":[{"med_name":"med1","dosage":"10mg","frequency":"daily"},{"med_name":"med2","dosage":"20mg","frequency":"daily"}],"Cstm_PF_ADG_URT_Substance_Use":{"dimension1_comment":"dimension 1 - tab1","Textbox1":"text - tab1"},"Cstm_PF_ADG_Discharge_Note":{"prior_auth_no_comm":"auth no - tab2"},"Cstm_PF_ADG_URT_Clinical_Plan":{"cca_cs_dhs_details":"details - tab2"},"container":{"Cstm_PF_Name":{"first_name":"same text for textbox - footer","last_name":"second textbox - footer"},"Cstm_PF_ADG_URT_Demographics":{"new_field":"mapped demo - footer"},"grid2":[{"Cstm_PF_ADG_COMP_Diagnosis":{"diagnosis_label":"knee","diagnosis_group_code":"leg"}},{"Cstm_PF_ADG_COMP_Diagnosis":{"diagnosis_label":"ankle","diagnosis_group_code":"leg"}}]},"submit":true}}

const result = 
  Array.from
    ( keySearch(response, "Cstm")
    , ([ table, values ]) =>
        ({ table, values })
    )

console.log(result)

Answer 3

Here's a working version. I call the main function recursively if the value is either an array or an object. Also passing in the current state of the tallying array each time.

function getNamesAndValues(data, id, tablesAndValues = []) {
  const res = data;
 
  Object.entries(res).map(([key, value]) => {
    const newKey = key.split('_')[0].toLowerCase();
    const item = res[key];

    if (newKey === id) {
      tablesAndValues.push({
        table: key,
        values: value
      });
    }
    
    if(Array.isArray(item)) {
        return item.map(el => getNamesAndValues(el, id, tablesAndValues));
    }

    if(typeof item === 'object') {
        return getNamesAndValues(item, id, tablesAndValues);
    }

  })

  return tablesAndValues;
}

console.log(getNamesAndValues(response.data, 'cstm'));

Answer 4

You just need to call push to tablesAndValues inside the else statement with the rest operator and pass the value and id as parameters

const response = {
  "data": {
    "Cstm_PF_ADG_URT_Disposition": {
      "child_welfare_placement_value": ""
    },
    "Cstm_PF_ADG_URT_Demographics": {
      "school_grade": "family setting",
      "school_grade_code": ""
    },
    "Cstm_Precert_Medical_Current_Meds": [
      {
        "med_name": "med1",
        "dosage": "10mg",
        "frequency": "daily"
      },
      {
        "med_name": "med2",
        "dosage": "20mg",
        "frequency": "daily"
      }
    ],
    "Cstm_PF_ADG_URT_Substance_Use": {
      "dimension1_comment": "dimension 1 - tab1",
      "Textbox1": "text - tab1"
    },
    "Cstm_PF_ADG_Discharge_Note": {
      "prior_auth_no_comm": "auth no - tab2"
    },
    "Cstm_PF_ADG_URT_Clinical_Plan": {
      "cca_cs_dhs_details": "details - tab2"
    },
    "container": {
      "Cstm_PF_Name": {
        "first_name": "same text for textbox - footer",
        "last_name": "second textbox - footer"
      },
      "Cstm_PF_ADG_URT_Demographics": {
        "new_field": "mapped demo - footer"
      },
      "grid2": [
        {
          "Cstm_PF_ADG_COMP_Diagnosis": {
            "diagnosis_label": "knee",
            "diagnosis_group_code": "leg"
          }
        },
        {
          "Cstm_PF_ADG_COMP_Diagnosis": {
            "diagnosis_label": "ankle",
            "diagnosis_group_code": "leg"
          }
        }
      ]
    },
    "submit": true
  }
};

function getNamesAndValues(data, id) {
  const tablesAndValues = [],
        res = data;
 
  Object.entries(res).map(([key, value]) => {
    const newKey = key.split('_')[0].toLowerCase();
    
    // console.log(newKey) // -> 'cstm'
    
    if (newKey === id) {
      tablesAndValues.push({
        table: key,
        values: value
      });
    } else {
      // I can log value and key and see what I want to push 
      // to the tablesAndValues array, but I can't seem to get 
      // how to push the nested items.
      
      // console.log(value);
      // console.log(key);
      
      tablesAndValues.push(...getNamesAndValues(value, id))
    }
  });
  
  return tablesAndValues;
}

console.log(getNamesAndValues(response.data, 'cstm'));

Or in shorter way

function getNamesAndValues2(data, id) {
    return Object.entries(data).reduce((arr, [key, value]) => {
        arr.push(
            ...(key.split('_')[0].toLowerCase() === id ? [{ table: key, values: value }] : getNamesAndValues(value, id))
        );
        return arr
    }, []);
}

Answer 5

To achieve the result with a single push, one can pass the result table to the function when called recursively, but default it to an empty table on the first call. I've also changed .map to .forEach since the return value is not used:

const response = {
  "data": {
    "Cstm_PF_ADG_URT_Disposition": {
      "child_welfare_placement_value": ""
    },
    "Cstm_PF_ADG_URT_Demographics": {
      "school_grade": "family setting",
      "school_grade_code": ""
    },
    "Cstm_Precert_Medical_Current_Meds": [
      {
        "med_name": "med1",
        "dosage": "10mg",
        "frequency": "daily"
      },
      {
        "med_name": "med2",
        "dosage": "20mg",
        "frequency": "daily"
      }
    ],
    "Cstm_PF_ADG_URT_Substance_Use": {
      "dimension1_comment": "dimension 1 - tab1",
      "Textbox1": "text - tab1"
    },
    "Cstm_PF_ADG_Discharge_Note": {
      "prior_auth_no_comm": "auth no - tab2"
    },
    "Cstm_PF_ADG_URT_Clinical_Plan": {
      "cca_cs_dhs_details": "details - tab2"
    },
    "container": {
      "Cstm_PF_Name": {
        "first_name": "same text for textbox - footer",
        "last_name": "second textbox - footer"
      },
      "Cstm_PF_ADG_URT_Demographics": {
        "new_field": "mapped demo - footer"
      },
      "grid2": [
        {
          "Cstm_PF_ADG_COMP_Diagnosis": {
            "diagnosis_label": "knee",
            "diagnosis_group_code": "leg"
          }
        },
        {
          "Cstm_PF_ADG_COMP_Diagnosis": {
            "diagnosis_label": "ankle",
            "diagnosis_group_code": "leg"
          }
        }
      ]
    },
    "submit": true
  }
};

function getNamesAndValues(data, id, tablesAndValues = []) {
  const res = data;
 
  Object.entries(res).forEach(([key, value]) => {
    const newKey = key.split('_')[0].toLowerCase();
    if (newKey === id) {
      tablesAndValues.push({
        table: key,
        values: value
      });
    } else {
        getNamesAndValues( value, id, tablesAndValues);    }
  });
    return tablesAndValues;
}

console.log(getNamesAndValues(response.data, 'cstm'));