Question 191777 in Javascript Question posted in
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Javascript – Expressions in my template literal don't get updated

I define the variable description as a template literal with an expression in it. When I then use description later in runScenario, the expression returns what money started as, not what it currently is.

var money = 100;
var description = `You have ${money} money`;

function payday { 
    money += 50;
}

function runScenario {
    console.log(description);
}

No matter how many times payday is run, the output is always "You have 100 money".

I expected that the expression would be evaluated every time the variable is called, but I’m finding that the expression is only evaluated when defining the variable.

How do I fix this? What could I do instead?

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2

Answers


  1. 0

    The expression is evaluated instantly, and only once, in your code. You can use an arrow function to apply the template on demand:

    let money = 100;
const getDescription = () => `You have ${money} money`;

function payday() { 
  money += 50;
}

function runScenario() {
  console.log(getDescription());
}

runScenario();
payday();
runScenario();
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  2. 0

    Description variable value is assigned at line 2 hence it won’t change although money variable is change

    var money = 100;
var description = `You have ${money} money`;

function payday { 
    money += 50;
    description = `You have ${money} money`;
}

function runScenario {
    console.log(description);
}

    Or create function that will return description

    const getDescription = () => `You have ${money} money`;
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