是否可以重写数组中的所有值而无需在JavaScript中进行for循环？

Question

Let's suppose that we have an array (myArray) with data like this:

0: myArray
   content: 'something'
   date: '15.5.2015'
   name: 'Abc'
1: myArray
   content: 'text'
   date: '15.5.2015'
   name: 'Bla'
2: etc ...

Now for rewriting all values (into eg empty string) of one object properties in this array (for example: 'content') I would use for loop like this:

for(var i = 0; i < myArray.length; i++){
  myArray[i].content = '';
}

So result of this would be:

0: myArray
   content: ''
   date: '15.5.2015'
   name: 'Abc'
1: myArray
   content: ''
   date: '15.5.2015'
   name: 'Bla'
2: etc ...

My question is: Is possible to do same result without using loop in javascript? Something like this:

myArray[all].content.RewriteInto('');

Tnx for ideas.

Answer 1

Anything you do will end up looping in some fashion. However, you don't have to loop...

because we now have functional array methods! You're probably looking for map or reduce , perhaps both, since you want to transform (map) each element and/or combine them into one (reduce).

As an example, we can take your data and return a string with all of the content fields concatenated using:

 var data = [{ content: 'something', date: '15.5.2015', name: 'Abc' }, { content: 'text', date: '15.5.2015', name: 'Bla' }]; var result = data.map(function(it) { return it.content; }).join(' '); document.getElementById('r').textContent = JSON.stringify(result); 

 <pre id="r"></pre> 

To remove the content field from each item, without modifying the input, you can:

 var data = [{ content: 'something', date: '15.5.2015', name: 'Abc' }, { content: 'text', date: '15.5.2015', name: 'Bla' }]; var result = data.map(function(it) { return {date: it.date, name: it.name}; }); document.getElementById('r').textContent = JSON.stringify(result); 

 <pre id="r"></pre> 

Answer 2

You should look at the map function . Use it like this :

myArray.map(function (data) {
    return data.content = 'value';
}

Answer 3

As the first comment on your question points out you always have to use a loop, but you could monkey patch the Array using prototype like:

Array.prototype.rewriteInto = function(key, rewriteVal){
  for(var k in this){
    this[k][key] = rewriteVal;
  }
};

var testData = new Array();
testData.push({
  content: 'something',
  date: '15.5.2015',
  name: 'Abc',
});

testData.push({
  content: 'something',
  date: '15.5.2015',
  name: 'bla',
});

console.log(testData);

testData.rewriteInto('content', '');
console.log(testData);

So you don't have to rewrite the loop all the time you want to use this functionality.

See example