Created
July 3, 2020 01:00
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| /* | |
| There's two ways to see if the answer matches more efficiently | |
| Both of ways use arrays to contain the answers, and loop through them to find the answer | |
| These are better beacuse | |
| 1. they're less lines, and easier to read from a developer's perspective | |
| 2. they're also more flexible; say if you wanted to use this code in another app, | |
| or change the words themselves for any other reason, it's easy to edit the answers array | |
| and use the same code again because the actual answers are defined in one place rather | |
| than in each "if" case over and over again | |
| */ | |
| // 1. finding the answer from the array via a for loop | |
| const getUserChoiceLoop = userInput => { | |
| const answers = [ | |
| "rock", | |
| "paper", | |
| "scissors" | |
| ] | |
| // for loop, if you haven't learned about these you will soon! | |
| for (let i = 0; i < answers.length; i++) { | |
| if (userInput === answers[i]) { | |
| return answers[i]; | |
| } | |
| } | |
| /* | |
| the rest of this code will only be reached if the above return was never hit; | |
| meaning nothing in the array matched userInput and therefore we know that userInput | |
| isn't rock, paper, or scissors | |
| */ | |
| // this throws an error to the console | |
| throw("Invalid user input!"); | |
| } | |
| // 2. Using Array "higher order functions" | |
| // (this one's a lot more advanced, just wanted to give you a glimpse at this stuff if you were curious) | |
| const getUserChoiceArrayFunction = userInput => { | |
| const answers = [ | |
| "rock", | |
| "paper", | |
| "scissors" | |
| ] | |
| /* | |
| the "array.filter()" function of an array takes a function as input | |
| it will call the function with each element of the array, and make | |
| a new array containning all elements that caused the function to return true | |
| further reading: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/filter | |
| */ | |
| /* | |
| in this case, it will run thru each element of the answer array, | |
| and any answer that matches the userInput will be added to the matchedAnswers array | |
| */ | |
| let matchedAnswers = answers.filter(answer => userInput === answer) | |
| // ex. if userInput = "paper", matchedAnswers = ["paper"] | |
| // or, if userInput = "potato", matchedAnswers = [] (empty array) | |
| // if one of them matched, the length of the array will be 1 | |
| if (matchedAnswers.length === 1) { | |
| return matchedAnswer[0]; | |
| } | |
| // if none of them matched, the userInput is invalid, and an error is thrown | |
| else { | |
| throw ("Invalid user input") | |
| } | |
| } |
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