What I am trying to accomplish, being able to use the filter function to filter out the people that have the age: 21 and the color: blue.
Any suggestions on how to make it work? Thanks in advance.
Here is my code:
var arr = [ { name: 'Steve', age: 18, color: 'red' }, { name: 'Louis', age: 21, color: 'blue' }, { name: 'Mike', age: 20, color: 'green' }, { name: 'Greg', age: 21, color: 'blue' }, { name: 'Josh', age: 18, color: 'red' } ];
var filter = function(arr, criteria){
var filtered = []
for(var i=0; i<arr.length; i++){
if (arr[i] === criteria) {
filtered.push(arr[i])
}
return filtered;
}
}
console.log(filter(arr, { age: 21, color: 'blue' }));
Cant compare object with ===
Testing objects equality in NodeJS
You should add return
outside for-loop
var filter = function(arr, criteria){
return arr.filter( function(item){
return Object.keys(criteria).every(function(key) {
return item[key] == criteria[key];
});
});
}
The reason your solution is not working is because you cannot compare two objects using the equality operator, so you have to actually compare the properties of the objects, use a library like lodash or underscore with a built in comparison functino, or write a deep equals function yourself that iterates through the properties of each and returns false if at any point they are not equal.
Here is one possible solution:
var filter = function(arr, criteria){
var filtered = []
arr.forEach(function (item) {
if (item.age === criteria.age && item.color === criteria.color) {
filtered.push(item);
}
});
return filtered;
};
You'll have to loop over those Objects in your Array and test for their properties and property values. Here's a backward compatible way to do it:
function hasCompObjPropsAndVals(obj, compObj){
var l = 0, c = 0;
for(var i in compObj){
l++;
for(var p in obj){
if(i === p && compObj[i] === obj[p]){
c++;
break;
}
}
}
if(l !== 0 && l === c){
return true;
}
return false;
}
function filter(objArray, compObj){
var res = [];
for(var i=0,l=objArray.length; i<l; i++){
var o = objArray[i];
if(hasCompObjPropsAndVals(o, compObj)){
res.push(o);
}
}
return res;
}
var arr = [ { name: 'Steve', age: 18, color: 'red' }, { name: 'Louis', age: 21, color: 'blue' }, { name: 'Mike', age: 21, color: 'green' }, { name: 'Greg', age: 21, color: 'blue' }, { name: 'Josh', age: 18, color: 'red' } ];
console.log(filter(arr, {age: 21, color: 'blue'}));
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