I'm trying to resolve my problem, but I don't have anymore ideas.
I want to create function to return array of values according of type variable.
I want to check that the parameter which is sent to function is an array of string or array of webelements, and I want to return this array to other function to sort it.
Here is my code:
private static returnByType(unSortedElements) {
var i = 0;
var unSorted = [];
if (typeof unSortedElements[0] === 'string') {
unSorted = unSortedElements;
return unSorted;
} else {
return unSortedElements.each((eachName) => {
eachName.getText().then((name) => {
unSorted[i] = name;
i++;
})
})
}
}
If I pass string array to this function, it returns array with this strings, but when I pass there a list of webelements I get an empty array (in else block).
How I should return unSorted from else block?
If you are dealing with promise, you can't just return value, it will always be a promise. Your code should be probably something like this:
private static returnByType(unSortedElements) {
var i = 0;
var unSorted = [];
if (typeof unSortedElements[0] === 'string') {
unSorted = unSortedElements;
// Promise.resolve(unSorted) to unify with else
return Promise.resolve(unSorted);
} else {
// return type will be Promise<[]>
return Promise.all(unSortedElements.map((eachName) => eachName.getText()));
}
}
Return type of the function now will be Promise<[]>. Then you can use it like:
returnByType(args).then((unsorted) => ...);
for Promise.all() refer to documentation.
for Promise.resolve() refer to documentation.
Related
So i have an array with many objects, all those objects have maybe arrays and objects, so this similar tree continuese, and I want to do a search that searches all values on all those arrays and objects and returns back.
Here is the function I have but doesn't work And I think it works only with the first object but this still is not working.
Here is the function I do have (its broken):
const findIn = (arr, query) => {
let queryFormatted = query.toLowerCase().replace(/\s/g, ' ');
return arr.filter((obj) =>
Object.keys(obj).some((key) => {
if (typeof obj[key] === 'string') {
return obj[key]
.toLowerCase()
.replace(/\s/g, ' ')
.includes(queryFormatted);
}
return false;
})
);
};
Sample of Data (that needs to be searched):
:
If I understand your question correctly, and you want to check whether any nested string is a substring of your query, returning true or false, here is a solution:
const findIn = (elem, query) => {
query = query.toLowerCase().replace(/\s/g,'');
if (!(elem instanceof Object)){
if (typeof elem == "string"){
return elem.toLowerCase().replace(/\s/g,'').includes(query);
}
return false
}
if (Array.isArray(elem)){
for (const nested of elem){
if (findIn(nested,query)){
return true;
}
}
return false;
}
for (const nested of Object.values(elem)){
if (findIn(nested,query)){
return true;
}
}
return false;
}
Note that this might not work in some specific cases but should be enough if you are parsing json into a js object and then calling the function.
I'm having problems when trying to return a value encountered from a .map using Javascript. There's my code:
function LineaDeSuccion() {
const carga = vm.cargaTotal / vm.numeroEvaporadores;
vm.succion.map(i => {
if (i.temperatura == vm.tempSel) {
const cargas = Object.keys(i).map(function(key) {
return i[key];
});
// I need to return this value in my function
return getKeyByValue(i, closest(cargas, carga));
}
// Obviously I can't do it because the value it's encapsulated into the map callback.
// How can I solve it?
return value;
});
}
One approach is to use Array.prototype.find to find the value you want in the array, then perform the transformation you need once you have it.
function LineaDeSuccion() {
const carga = vm.cargaTotal / vm.numeroEvaporadores;
const i = vm.succion.find(i => i.temperatura == vm.tempSel);
if (i === undefined) {
throw Error("can't find what I want in the array");
}
const cargas = Object.keys(i).map(function (key) {
return i[key];
});
return getKeyByValue(i, closest(cargas, carga));
}
Note that this approach will not iterate over the entire array but break out of the find loop immediately once a match is found. If there are several elements i in the array which satisfy the condition i.temperatura == vm.tempSel, this will return the first match, not the last.
If you want to return a value outside of your map, you'll have to set a variable that lives outside of your map, and then set that value within your map:
function LineaDeSuccion() {
const carga = vm.cargaTotal / vm.numeroEvaporadores;
let value = "defaultValue"; // default value
vm.succion.map(i => {
if (i.temperatura == vm.tempSel) {
const cargas = Object.keys(i).map(function(key) {
return i[key];
});
value = getKeyByValue(i, closest(cargas, carga)); // new set value
}
});
return value;
}
I have always been confused about the best way to handle this. The method I have been using in the past works but it seems like there has to be a better way.
Below I have a section of code that I'm wanting to return item for the function getData. Problem is in the example below it's returning for the forEach function not the getData function.
function getData() {
var array = ["element1","element2"];
array.forEach(function (item) {
if (item == "element2") {
return item;
}
});
}
I have been doing something like this to overcome this.
function getData() {
var array = ["element1","element2"];
var returnValue;
array.forEach(function (item) {
if (item == "element2") {
returnValue = item;
}
});
if (returnValue) {
return returnValue;
}
}
Is there a better way to handle this? Seems like those extra 4 lines of code just create confusion and clutter in my code.
You could use Array#some
The some() method tests whether some element in the array passes the test implemented by the provided function.
function getData() {
var array = ["element1","element2"];
var returnValue;
array.some(function (item) {
if (item == "element2") {
returnValue = item;
return true;
}
});
return returnValue;
}
Or, if you use ES6, use Array#find
The find() method returns a value in the array, if an element in the array satisfies the provided testing function. Otherwise undefined is returned.
function getData() {
var array = ["element1","element2"];
return array.find(item => item == "element2");
}
You can readily do this with Array#indexOf:
function getData() {
var array = ["element1","element2"];
var index = array.indexOf("element2");
return index === -1 ? null : array[index];
}
In that case, it works because what you're looking for is an === match for what you have. The more general case is a case for Array#find, which is an ES2015 thing but you can easily shim/polyfill it for ES5 and below:
function getData() {
var array = ["element1","element2"];
return array.find(function (item) {
return item == "element2";
});
}
...which lets you specify the match based on a more complex condition.
You could just use indexOf:
return array[array.indexOf("element2")];
If it doesn't find the value, the index will be -1. And index -1 of any array will be undefined.
I need a function to check if an object exists in a tree.
I recursively run through the tree and use lodash to check for equality of objects:
var objectInResultList = function (obj, list) {
list.forEach(function (item) {
if (_.isEqual(item, obj) === true) {
return true
}
else if (item.children.length > 0) {
return objectInResultList(obj, item.children);
}
});
return false;
};
var item = {"name":"Enterprise1.1","description": "testTest","children":[]};
var resultList = [{"name":"Enterprise1.1","description": "testTest","children":[{"name":"Enterprise1.1","description": "testTest","children":[]}]}];
var ret = objectInResultList(item, resultList);
alert(ret);
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/1.2.1/lodash.min.js"></script>
The function should return true if the item is in the list and otherwise return false, but currently it always returns false.
Can someone find my problem?
JSFiddle
You are missing a couple of things.
A minor thing - your predicate is not returning false if the objects don't match and it has no children.
You are returning true/false from the predicate, but aren't using it anywhere so objectInResultList always returns false.
Rather than using forEach, it is easier to use find or findIndex, and the use the result of that to determine what to return from objectInResultList. For example if find returns undefined because of no match, then you return false.
In this case, you are using a tree with multiple lists, so using find makes more sense than findIndex.
var objectInResultList = function (obj, list) {
// call find to get the matching object
var match = list.find(function (item) {
if (_.isEqual(item, obj) === true) {
return true;
}
else if (item.children.length > 0) {
return objectInResultList(obj, item.children);
}
else {
return false;
}
});
// if match is undefined return false. If we found a match, return true
return !_.isUndefined(match);
};
var item = {"name":"Enterprise1.1","description": "testTest","children":[]};
var resultList = [{"name":"Enterprise1.1","description": "testTest","children":[{"name":"Enterprise1.1","description": "testTest","children":[]}]}];
var ret = objectInResultList(item, resultList);
alert(ret);
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/1.2.1/lodash.min.js"></script>
forEach() has no return-value and it ignores any returned value. So returning true or false in the search-function is useless.
You should use a better iterator-function.
var objectInResultList = function (obj, list) {
function search(item){
if(item == null) return false;
if(_.isArray(item)) return _.some(item, search);
if(_.isEqual(item, obj)) return true;
return search(item.children);
}
return search(list);
};
I'm just making a function for checking a value of something in my object array, but for some reason it keeps returning undefined. Why is that?
Demo: http://jsfiddle.net/cNYwz/1/
var data = [{
"Key": "1111-1111-1111",
"Email": "test#test.com"
}, {
"Key": "2222-2222-2222",
"Email": "test#boo.com"
}];
function getByKey(key) {
data.forEach(function (i, val) {
if (data[val].Key === key) {
return data[val].Key;
} else {
return "Couldn't find";
}
});
}
var asd = getByKey('1111-1111-1111');
console.log(asd);
In your function, you're returning from the function passed to forEach, not from getByKey.
You could adapt it like this :
function getByKey(key) {
var found = null;
data.forEach(function (val) {
if (val.Key === key) {
found = val;
}
});
return found;
}
But this would iterate over all elements, even if the item is immediately found. That's why you'd better use a simple for loop :
function getByKey(key) {
for (var i=0; i<data.length; i++) {
if (data[i].Key === key) {
return data[i];
}
}
}
Note that I also adapted your code to return the value, not the key. I suppose that was the intent. You might also have been confused with another iteration function : the first argument passed to the callback you give to forEach is the element of the array.
Your function getByKey has no return statement. The two returns are for the anonymous function used by forEach.
You're not returning anything to the outer scope, try this alternative:
function getByKey(key) {
var result = data.filter(function (i, val) {
return data[val].Key == key;
});
return result.length ? result : 'Not found';
}
Try storing the positive result as a variable, and then returning that variable (or a "Couldn't find" in case nothing is written) at the end of the function after the forEach loop.
function getByKey(key) {
var result;
data.forEach(function (val, i) {
if (data[val].Key === key) {
result = data[val].Key;
}
});
return result || "Couldn't find";
}
In addition to the ideas in the other answers, you're better off using Array.prototype.some, rather than forEach. That will let you stop when you find the first match:
function getByKey(key) {
var found = null;
data.some(function (val) {
if (val.Key === key) {
found = val;
return true; //stop iterating
}
});
return found;
}
You might also consider using filter, which can return an array containing just the objects where key matches:
function filter_array_by_key(key){
return data.filter(function(v){
return v.Key===key;
};
}
To get the first matching object, you can then use filter_array_by_key(key)[0], which will yield undefined if there was no match.