How to get object property dynamically using a custom function-CodePudding

I have a funciton that accept a property name

func(propertyName) {
  return object[propertyName];
}

so by calling func('value') will return the object.value

However the object is complex, so it has inner props

What I want to do is to be able to do that func('property1.property2')

What is the best way to do that?

CodePudding user response：

You can pass the inner object like in the sample below:

function getVal(obj, propertyName) {
  if (obj){
     return obj[propertyName];
  }
}

var o = { 
          prop1: {
            prop2: {
              prop3: 'john'
       }
}};

console.log(getVal(o.prop1.prop2, 'prop3'));

If you just want to reference an inner property, you can protect from getting null exception using the optional chaining operator (?.)

const x = {prop1: {prop2: 'john'}};
console.log(x?.prop1?.prop2?.prop3?.prop4); //undefined instead of error

optional chaining operator- https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Optional_chaining

CodePudding user response：

try this:

example data: a={b:{c:"hellooo"}};

function: function getValue(object,propertyName){ return propertyName.split(".").reduce((a,c)=>a[c],object); }

response:

getValue(a,"b.c") = hellooo

CodePudding user response：

function getValueByKeyPath(obj, path) {
  return String(path)
    .split('.')
    .reduce((value, key) => value?.[key], Object(obj))
}

const sampleData = {
  foo: {
    value: 'foo',
    bar: {
      value: 'bar',
      baz: {
        value: 'baz',
      },
    },
  },
};

console.log(
  "getValueByKeyPath(sampleData, 'foo.bar.baz.value') ...",
  getValueByKeyPath(sampleData, 'foo.bar.baz.value')
);
console.log(
  "fail safe ... getValueByKeyPath(sampleData, 'foo.biz.baz.value') ...",
  getValueByKeyPath(sampleData, 'foo.biz.baz.value')
);

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