Develop Reference

JSON structure in javascript [closed]

Closed. This question needs details or clarity. It is not currently accepting answers.
Want to improve this question? Add details and clarify the problem by editing this post.
Closed 6 days ago.
Improve this question
I am trying to create a javascript structure that looks like that:
[{'red': {color:'red},...}]
starting with an array of colors:
const COLORS = ['red','yellow']
This is what I have tried:
const finalArray = COLORS.map(color => ({ [color]: { color } }))
However this produces an array that looks like that:
[{red: {color:'red'}}]
instead of [{'red': {color:'red'}}]
Which is not the same and will prevent the library I am using from understanding the array.
Any idea is welcome.
I edited the question since there where some typos. Hope it’s clearer now.
Thanks

What are the differences between:
[{red: {color:'red'}}]
// and
[{'red': {color:'red'}}]
If it's only a quote related matters, you can do like:
COLORS.map(color => ({ [`'${color}'`]: { color } }));

These are just two ways of representing the same array/object. If you need a string containing the canonical representation of the array/object (with double quotes around the names of the properties), you can use JSON.stringify(finalArray).
Please note this will quote ALL your property names, like in:
[{"red":{"color":"red"}}]
And please note the above is a string, as if you did:
finalString = '[{"red":{"color":"red"}}]'
(Note: this question has been closed, and I agree it's not clear enough. But it's quite evident that the user is confusing the internal structure of an array/object with its external representation, and with the way the array/object is shown by a development environment, browser, etc. As this is a very common problem, mostly in new programmers or newcomers to a tool, the question and the answers may still be helpful.)

Javascript form validation pattern [closed]

Closed. This question needs details or clarity. It is not currently accepting answers.
Want to improve this question? Add details and clarify the problem by editing this post.
Closed 6 years ago.
Improve this question
I'm trying to validate that two characters and a number were correctly input.
var studentValid = /^[MTWTF][AL][1-9]$/i;
if (studentValid.test(studentTemp.value))
{
alert("true");
}
else
{
alert("false");
}
Yet everything I enter turns out false?

The problem is with your regexp (/^[MTWTF][AL][1-9]$/i). What this tells you is that you first want one of the characters M,T,W,T or F, and after that either A or L and finaly a number (and nothing before or after this).
So for example
ML4, WA5, FL9
will give you true
while
AM9, ML0, MMA5, MA99
will give you false.
Is this the pattern you are trying to match? There is nothing else wrong with your code and a valid value will give you true, for example:
var studentValid = /^[MTWTF][AL][1-9]$/i;
var value = 'MA9';
if (studentValid.test(value))
{
alert("true");
}
else
{
alert("false");
}
When working with regexp, it can be very usefull to use a tool to help you build it, check out https://regex101.com/r/A5FOIh/3 where you can try your different studentTemp.value to see if they match.

How to ask in Javascript? [closed]

Closed. This question needs to be more focused. It is not currently accepting answers.
Want to improve this question? Update the question so it focuses on one problem only by editing this post.
Closed 6 years ago.
Improve this question
I want to write a line of code which asks a question and the user has to enter a number. The number is then stored as a variable and used throughout the rest of the script. Such as:
fit1 = "What is your fitness level?"
level = the number the user had entered
something like that. Can't really explain it properly
P.S. I'm writing my code out in gedit because thats what my uni uses.

You can use a prompt like shown below:
var n = prompt("Fitness level");
console.log(n);

window.level = window.prompt('What is my fitness level?');
console.log(window.level); //save in glonal space of window

You can use the Prompt command, and cast the string answer to type number :
var number = parseInt(prompt('Give me a number', '0'));
alert('You said: ' + number);

Is this eval Evil? [closed]

Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
Questions concerning problems with code you've written must describe the specific problem — and include valid code to reproduce it — in the question itself. See SSCCE.org for guidance.
Closed 9 years ago.
Improve this question
Writing a function in JavaScript. The plan is the function creates an object, which requires boolean statements as parameters. Something like this ->
var foo = new fuzz("pie < squirrel", "monkey === banana");
My question is - Is this evil?
*Note - * Inside the function 'fuzz' I will run checks on the values of the parameters. (Check string.length etc). I think this is how one is meant to use eval, it just has such a bad reputation on t'up web.
Thanks

Summing up the conclusions in the comments: write a simple rule evaluation engine! E.g.:
var variables = { ... };
function niceEval(condition) {
var operands = condition.match(/(\w+)\s+(\S+)\s+(\w+)/);
switch (operands[2]) {
case '<' :
return variables[operands[1]] < variables[operands[3]];
...
}
}
This also gives you a lot more control over possibly occurring errors than blindly evaling a string.

i am making a simple calculator(+,-,*,/ and cls) how can i get two input strings and perform operation [closed]

Closed. This question needs details or clarity. It is not currently accepting answers.
Want to improve this question? Add details and clarify the problem by editing this post.
Closed 9 years ago.
Improve this question
i know how to add two strings but don't know how will i obtain which no user pressed and obtain their string something to do with OnClick ?

You can get the id of the clicked button and adding it's string with the number it hab with something like that in your activity:
void methodCalledByOnClick(View v) {
switch(v.getId()) {
case R.id.btn_NrOne:
editTextWhereNumbersHaveToBeDisplayed.setText(
editTextWhereNumbersHaveToBeDisplayed.getText() + v.getText()
);
break;
case R.id.btn_NrTwo:
and so on...
}
}
To get the Number for calculation out of the textEdit please have a look at te answer from Veer Shubhranshu Shrivastav.
Also: Please try to be more precise in future questions you may have!

Do one thing, restrict the user to enter only numeric value in the Textbox.
In android EditText has a attribute inputType make it number. Then the user can only enter number. Then for thread-safe program check the ASCII value of the input between 48-54 (0-9)
Then you use
EditText ed = (EditText) findViewById(R.id.Edit1);
int num = Integer.parseInt(ed.getText); ///You got the number.

Your question did not state whether this is for an android app or a HTML app. In case you are referring to an android app then I recommend going through the Android training. That explains the basics on how to access views etc.
https://developer.android.com/training/basics/firstapp/index.html