JavaScript: Tally Winning Scores
featuring for loop, conditional ternary operator and template literal
for loop
for (let i=0; i<a1.length; i++) { ... }
The for loop iterates through two conditional ternary operator instructions described below. let declares block-scoped variable i local to the for loop. i=0 sets the starting index. i<a1.length limits the loop to three iterations, since arrays a1 and a2 contain three elements each. i++ indicates that each iteration will progress by one index step at a time, or a1[0], a1[1], a1[2] for all three iterations.
conditional ternary operator
a1[i] > a2[i] ? c1++ : null
? is the conditional ternary operator which is used to shorten the code, and which works with the : operator. The comparisona1[i] > a2[i] contains the > comparison operator which takes the two operands a1[i] and a2[i] which are individual performance category scores values, based on the context of Rock Off!. c1++ : null basically means that if the comparison returns true, then add 1 to the c1 counter, else return null—which has the effect of skipping to the next instruction.
To paraphrase: if a1[i] > a2[i] returns true, then add 1 to the c1 counter value, otherwise skip to the next instruction.
template literal
return `${c1}, ${c2}: Alice made "Kurt" proud!`
JavaScript’s template literals are string literals which can embed expressions. ${c1} embeds the value stored in c1. `...` accent marks are used like quotation marks to specify template literal formatting. : Alice made "Kurt" proud! is simply a hard-coded text string. solve([47, 67, 22], [26, 47, 12] returns 3, 0: Alice made "Kurt" proud! because the 1st rock band scored higher than the 2nd in all three categories.
running the script
console.log(solve([47, 7, 2], [47, 7, 2]),'0, 0: that looks like a "draw"! Rock on!')
console.log(solve([47, 67, 22], [26, 47, 12]),'3, 0: Alice made "Kurt" proud!')
console.log(solve([25, 50, 22], [34, 49, 50]),'1, 2: Bob made "Jeff" proud!')Two arrays passed to the solve() function can now be seen above. [47, 7, 2] contains a set of three numbers. Each number represents total points scored in a specific category. '0, 0: that looks like a "draw"! Rock on!' is the result expected to be seen in the CLI. 0, 0 indicates that both bands failed to win in a single category.
