* feat(tools): add seed/solution restore script * chore(curriculum): remove empty sections' markers * chore(curriculum): add seed + solution to Chinese * chore: remove old formatter * fix: update getChallenges parse translated challenges separately, without reference to the source * chore(curriculum): add dashedName to English * chore(curriculum): add dashedName to Chinese * refactor: remove unused challenge property 'name' * fix: relax dashedName requirement * fix: stray tag Remove stray `pre` tag from challenge file. Signed-off-by: nhcarrigan <nhcarrigan@gmail.com> Co-authored-by: nhcarrigan <nhcarrigan@gmail.com>
2.7 KiB
id, title, challengeType, videoUrl, forumTopicId, dashedName
| id | title | challengeType | videoUrl | forumTopicId | dashedName |
|---|---|---|---|---|---|
| 56533eb9ac21ba0edf2244ca | Using Objects for Lookups | 1 | https://scrimba.com/c/cdBk8sM | 18373 | using-objects-for-lookups |
--description--
Objects can be thought of as a key/value storage, like a dictionary. If you have tabular data, you can use an object to "lookup" values rather than a switch statement or an if/else chain. This is most useful when you know that your input data is limited to a certain range.
Here is an example of a simple reverse alphabet lookup:
var alpha = {
1:"Z",
2:"Y",
3:"X",
4:"W",
...
24:"C",
25:"B",
26:"A"
};
alpha[2]; // "Y"
alpha[24]; // "C"
var value = 2;
alpha[value]; // "Y"
--instructions--
Convert the switch statement into an object called lookup. Use it to look up val and assign the associated string to the result variable.
--hints--
phoneticLookup("alpha") should equal "Adams"
assert(phoneticLookup('alpha') === 'Adams');
phoneticLookup("bravo") should equal "Boston"
assert(phoneticLookup('bravo') === 'Boston');
phoneticLookup("charlie") should equal "Chicago"
assert(phoneticLookup('charlie') === 'Chicago');
phoneticLookup("delta") should equal "Denver"
assert(phoneticLookup('delta') === 'Denver');
phoneticLookup("echo") should equal "Easy"
assert(phoneticLookup('echo') === 'Easy');
phoneticLookup("foxtrot") should equal "Frank"
assert(phoneticLookup('foxtrot') === 'Frank');
phoneticLookup("") should equal undefined
assert(typeof phoneticLookup('') === 'undefined');
You should not modify the return statement
assert(code.match(/return\sresult;/));
You should not use case, switch, or if statements
assert(
!/case|switch|if/g.test(code.replace(/([/]{2}.*)|([/][*][^/*]*[*][/])/g, ''))
);
--seed--
--seed-contents--
// Setup
function phoneticLookup(val) {
var result = "";
// Only change code below this line
switch(val) {
case "alpha":
result = "Adams";
break;
case "bravo":
result = "Boston";
break;
case "charlie":
result = "Chicago";
break;
case "delta":
result = "Denver";
break;
case "echo":
result = "Easy";
break;
case "foxtrot":
result = "Frank";
}
// Only change code above this line
return result;
}
phoneticLookup("charlie");
--solutions--
function phoneticLookup(val) {
var result = "";
var lookup = {
alpha: "Adams",
bravo: "Boston",
charlie: "Chicago",
delta: "Denver",
echo: "Easy",
foxtrot: "Frank"
};
result = lookup[val];
return result;
}