JavaScript Brain Teasers: Exercise Your Mind/

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Discussion: Your Code Deserves a Lift

Discussion: Your Code Deserves a Lift

Execute the code to understand the output and gain insights into scoping and hoisting concepts in JavaScript.

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Verifying the output

Now, it’s time to execute the code and observe the output.

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let temp = 25;
function displayTemperature() {
  console.log(`Current temperature: ${temp} °C`);
}
function forecastTemperature() {
  console.log(`Expected temperature: ${temp} °C`);
  var temp = 28;
}
displayTemperature();
forecastTemperature();

Understanding the output

You might have expected the output to be:

Current temperature: 25 °C
Expected temperature: 25 °C

But this code will actually output:

Current temperature: 25 °C
Expected temperature: undefined °C

Variable hoisting

In JavaScript, all declarations are subject to hoisting. This includes var, let, const, function, function*, and class declarations. Hoisting involves the automatic relocation of these declarations to the scope’s beginning, but their initialization is deferred until the execution flow hits the line where hoisting occurred. This process occurs before the code is executed, and it helps JavaScript handle references to variables and functions.

Consider the ...