Trim white spaces in both Object key and value recursively

Question

How do you trim white spaces in both the keys and values in a JavaScript Object recursively?

I came across one issue in which I was trying to \"clean\" a user suppli

Answer 1

The best solution I used is this. Check the documentation on replacer function.

var obj = {"data": {"address": {"city": "\n \r     New York", "country": "      USA     \n\n\r"}}};

var trimmed = JSON.stringify(obj, (key, value) => {
  if (typeof value === 'string') {
    return value.trim();
  }
  return value;
});

console.log(JSON.parse(trimmed));

Answer 2

You can just stringify it, string replace, and reparse it

JSON.parse(JSON.stringify(badJson).replace(/"\s+|\s+"/g,'"'))

Answer 3

epascarello's answer above plus some unit tests (just for me to be sure):

function trimAllFieldsInObjectAndChildren(o: any) {
  return JSON.parse(JSON.stringify(o).replace(/"\s+|\s+"/g, '"'));
}

import * as _ from 'lodash';
assert.true(_.isEqual(trimAllFieldsInObjectAndChildren(' bob '), 'bob'));
assert.true(_.isEqual(trimAllFieldsInObjectAndChildren('2 '), '2'));
assert.true(_.isEqual(trimAllFieldsInObjectAndChildren(['2 ', ' bob ']), ['2', 'bob']));
assert.true(_.isEqual(trimAllFieldsInObjectAndChildren({'b ': ' bob '}), {'b': 'bob'}));
assert.true(_.isEqual(trimAllFieldsInObjectAndChildren({'b ': ' bob ', 'c': 5, d: true }), {'b': 'bob', 'c': 5, d: true}));
assert.true(_.isEqual(trimAllFieldsInObjectAndChildren({'b ': ' bob ', 'c': {' d': 'alica c c '}}), {'b': 'bob', 'c': {'d': 'alica c c'}}));
assert.true(_.isEqual(trimAllFieldsInObjectAndChildren({'a ': ' bob ', 'b': {'c ': {'d': 'e '}}}), {'a': 'bob', 'b': {'c': {'d': 'e'}}}));
assert.true(_.isEqual(trimAllFieldsInObjectAndChildren({'a ': ' bob ', 'b': [{'c ': {'d': 'e '}}, {' f ': ' g ' }]}), {'a': 'bob', 'b': [{'c': {'d': 'e'}}, {'f': 'g' }]}));

Answer 4

I tried the solution JSON.stringify solution above, but it will not work with a string like '"this is \'my\' test"'. You can get around it using stringify's replacer function and just trim the values going in.

JSON.parse(JSON.stringify(obj, (key, value) => (typeof value === 'string' ? value.trim() : value)))

Answer 5

@RobG Thank you for the solution. Adding one more condition will not create more nested objects

function trimObj(obj) {
      if (obj === null && !Array.isArray(obj) && typeof obj != 'object') return obj;
      return Object.keys(obj).reduce(function(acc, key) { 
        acc[key.trim()] = typeof obj[key] === 'string' ? 
          obj[key].trim() : typeof obj[key] === 'object' ?  trimObj(obj[key]) : obj[key];
        return acc;
      }, Array.isArray(obj)? []:{});
    }

Answer 6

Similar to epascarello's answer. This is what I did :

import java.util.regex.Matcher;
import java.util.regex.Pattern;

........

public String trimWhiteSpaceAroundBoundary(String inputJson) {
    String result;
    final String regex = "\"\\s+|\\s+\"";
    final Pattern pattern = Pattern.compile(regex);
    final Matcher matcher = pattern.matcher(inputJson.trim());
    // replacing the pattern twice to cover the edge case of extra white space around ','
    result = pattern.matcher(matcher.replaceAll("\"")).replaceAll("\"");
    return result;
}

Test cases

assertEquals("\"2\"", trimWhiteSpace("\" 2 \""));
assertEquals("2", trimWhiteSpace(" 2 "));
assertEquals("{   }", trimWhiteSpace("   {   }   "));
assertEquals("\"bob\"", trimWhiteSpace("\" bob \""));
assertEquals("[\"2\",\"bob\"]", trimWhiteSpace("[\"  2  \",  \"  bob  \"]"));
assertEquals("{\"b\":\"bob\",\"c c\": 5,\"d\": true }",
              trimWhiteSpace("{\"b \": \" bob \", \"c c\": 5, \"d\": true }"));