Error Handling – try/catch
Name:
Date:
Class:
A
Quick Questions
Shade in the A or B circle for each question.
1. Does try/catch let a program keep running after an error?
2. Does the catch block run only when an error occurs in try?
3. Must 'try' be written in lowercase?
4. Must 'catch' be written in lowercase?
5. Does catch's parameter hold information about the error?
B
Match the Pairs
Draw a line connecting each item on the left to its match on the right.
| Left column | Right column | |
|---|---|---|
| 1try { risky(); } catch (e) { ... } | Ae | |
| 2catch (e) { console.log(e); } | BRuns this block only if an error occurred in try | |
| 3Prevents a program from crashing when an error occurs | Ctry { risky(); } catch (e) {} | |
| 4Holds information about the error inside catch | DWrong - 'try' must be lowercase | |
| 5Try { console.log(x); } catch (e) {} | ERuns the try block, and if it errors, runs catch | |
| 6try { console.log(x); } Catch (e) {} | FWrong - 'catch' must be lowercase |
C
Definitions
try...catch
D
Fill in the Blanks
Complete each line of code by filling in the missing parts.
1.
___ {
console.log(risky);
} catch (e) {
}
2.
try {
doSomething();
} _____ (e) {
console.log(e);
}
3.
try {
parseData();
} catch (___) {
}
4.
___ {
loadFile();
} catch (problem) {
}
5.
try {
connect();
} _____ (problem) {
console.log(problem);
}
E
Spot the Error
Shade in the letter of the line that contains an error.
Question 1
A
Try {
B
console.log(a);
C
} catch (e) {
D
}
Question 2
A
try {
B
consol.log(b);
C
} catch (e) {
D
}
Question 3
A
try {
B
console.log(c);
C
} Catch (e) {
D
}
Question 4
A
try {
B
console.log(d);
C
} catch (e) {
D
console.log(e)
E
}
Question 5
A
try {
B
console.log(g);
C
} catch (e) {
D
console.log(e);
E
}}
Answer Key
Error Handling – try/catch
Section A: Quick Questions
Q1
A — Yes
Q2
B — Yes
Q3
A — Yes
Q4
A — Yes
Q5
B — Yes
Section B: Match the Pairs
Q1
try { risky(); } catch (e) { ... } → Runs the try block, and if it errors, runs catch
Q2
catch (e) { console.log(e); } → Runs this block only if an error occurred in try
Q3
Prevents a program from crashing when an error occurs → try { risky(); } catch (e) {}
Q4
Holds information about the error inside catch → e
Q5
Try { console.log(x); } catch (e) {} → Wrong - 'try' must be lowercase
Q6
try { console.log(x); } Catch (e) {} → Wrong - 'catch' must be lowercase
Section C: Definitions
Q1
try...catch — Runs code in a try block, and if an error occurs, runs the catch block instead of crashing.Section D: Fill in the Blanks
Q1
try {
console.log(risky);
} catch (e) {
}Q2
try {
doSomething();
} catch (e) {
console.log(e);
}Q3
try {
parseData();
} catch (err) {
}Q4
try {
loadFile();
} catch (problem) {
}Q5
try {
connect();
} catch (problem) {
console.log(problem);
}Section E: Spot the Error
Q1
A — 'try' must be lowercase - a capital T causes an error.
Q2
B — 'console' is misspelled as 'consol'.
Q3
C — 'catch' must be lowercase - a capital C causes an error.
Q4
D — This line is missing a semicolon, but that's not required in JS.
Q5
E — There's an extra closing brace - only one } is needed here.