I am doing something like this in my application. I have sequence of Id values like ID1, ID2 etc. I am trying to fetch the ID value using for loop.
Concatenation doesn't seem to work.
function Save(count,Id1,Id2,Id3){
var response = [];
for(var i=1;i <= count; i++) {
value = `${'Id' + i}`;
alert(value);
}
}<input type="button" value="Submit" onclick="Save(3,1,2,3)" />You're creating a String "Id1", you cannot interpolate a variable name. But with ES6, you can use the rest parameters (...) to convert parts of your arguments to an Array:
function Save(count, ...ids) {
var response = [];
for (var i = 0; i < count; i++) {
value = ids[i];
alert(value);
}
}<input type="button" value="Submit" onclick="Save(3,1,2,3)" />Before ES6, you would have to use arguments (that would convert all arguments):
function Save() {
var response = [];
for (var i = 1; i <= arguments[0]; i++) {
value = arguments[i];
alert(value);
}
}<input type="button" value="Submit" onclick="Save(3,1,2,3)" />Or use eval, but don't. This is just for the example:
function Save(count, Id1, Id2, Id3, Id4) {
var response = [];
for (var i = 1; i <= count; i++) {
value = eval(`Id${i}`);
alert(value);
}
}<input type="button" value="Submit" onclick="Save(3,1,2,3)" />
That's not how interpolation works. It just inserts the value of the expression into a string. For example:
const age = 30
console.log(`I am ${age} years old!`) // Prints "I am 30 years old"
It doesn't interpret a string as an expression, which is what you apparently want to do. You could do that using eval, but this is most likely a step into the wrong direction.
If you want to iterate over the given values, just use an array instead:
function save (values) {
for (const value of values) {
alert(value)
}
}<input type="button" value="Submit" onclick="save([9, 8, 7])" />You can also iterate manually over the indexes, that can be useful if you need the index too, for example:
function save (values) {
for (let i = 0; i < values.length; i++) {
alert(`Index ${i} = ${values[i]}`)
}
}<input type="button" value="Submit" onclick="save([9, 8, 7])" />Or, if you want to keep your method of calling the function with multiple arguments (although the count argument is completely unnecessary), you can destructure the arguments into an array, like this:
function save (...values) {
for (let i = 0; i < values.length; i++) {
alert(`Index ${i} = ${values[i]}`)
}
}<input type="button" value="Submit" onclick="save(9, 8, 7)" />If you really wanted that count argument there, you could use function save (count, ...values). As a side note, there is also arguments, which is an array-like object that holds all the arguments passed to your current function, so you could iterate over that as well.
That doens't works because will throw a syntax exception. Its not the way you use interpolation. There are lots of ways to do what you need in a simple way:
function Save(ids) {
var response = [];
for(var i=0;i < ids.length; i++) {
value = ids[i];
console.log(value);
}
}
Save([1,2,3,4]);arguments constant:function Save(){
var response = [];
for(var i=0;i < arguments.length; i++) {
value = arguments[i];
console.log(value);
}
}
Save(1,2,3,4);
arguments object, you're getting undefined at the end because in the loop you set i <= arguments.length which will have an additional undefined argument. You'll need to set the stopping condition to i < arguments.length for example or maybe i <= arguments.length - 1.
Id1,Id2, ... but he wants to display the argument values1,2...