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/* | |
Assignment... | |
Write some code, that will flatten an array of arbitrarily nested arrays of integers into a flat array of integers. | |
e.g. [[1,2,[3]],4] -> [1,2,3,4]. | |
Your solution should be a link to a gist on gist.github.com with your implementation. | |
When writing this code, you can use any language you're comfortable with. The code must be well tested and documented | |
if necessary, and in general please treat the quality of the code as if it was ready to ship to production. | |
Try to avoid using language defined methods like Ruby's Array#flatten.* | |
*/ | |
/* | |
Solution.... | |
by chadsteele.com | |
I'm assuming this simple function would be included in a larger library, but for now, | |
I'll limit the scope to "tools". | |
You can execute in a browser or running >node test.js in your console | |
I'm also not depending on any external libraries although a production solution should | |
also not using prototypes, etc. to protect the global namespace | |
*/ | |
tools = { | |
flatten: (ary, result) => { | |
result = result || []; | |
if (!Array.isArray(ary)){ | |
result.push(ary); | |
return result; | |
} | |
ary.map(i => { | |
tools.flatten(i,result); | |
}); | |
return result; | |
}, | |
isEqual: (a, b) => { | |
if (a.length !== b.length) return false; | |
for (var i = 0; i < a.length; i++) { | |
if (a[i] != b[i]) return false; | |
} | |
return true; | |
}, | |
assert: (msg, expr) => { | |
if (expr) console.log('PASS ' + msg); | |
else console.log('FAIL ' + msg); | |
return expr; | |
}, | |
selfTest: () =>{ | |
var allPassed = true; | |
//test the example | |
allPassed &= tools.assert("[[1,2,[3]],4] -> [1,2,3,4]", tools.isEqual([1, 2, 3, 4], tools.flatten([[1, 2, [3]], 4]))); | |
//add strings | |
allPassed &= tools.assert("['one',[1,2,[3,'three']],4,[[[['five']]]]] -> ['one',1, 2, 3,'three', 4,'five']", tools.isEqual(['one',1, 2, 3,'three', 4,'five'], tools.flatten(['one',[1,2,[3,'three']],4,[[[['five']]]]]))); | |
// test crazy deep nesting with values, strings, and arrays | |
var crazy = "[1,[2,[3,[4,[5,[6,[7,[8,[9,['ten',[1,[2,[3,[4,[5,[6,[7,[8,[9,['twenty',[1,[2,[3,[4,[5,[6,[7,[8,[9,['thirty',[1,[2,[3,[4,[5,[6,[7,[8,[9,['forty',[1,[2,[3,[4,[5,[6,[7,[8,[9,['fifty'],1],2],3],4],5],6],7],8],9],'sixty'],1],2],3],4],5],6],7],8],9],70],1],2],3],4],5],6],7],8],9],80]]]]]]]]]]]]]]]]]]]]"; | |
var flatcrazy = "[1,2,3,4,5,6,7,8,9,'ten',1,2,3,4,5,6,7,8,9,'twenty',1,2,3,4,5,6,7,8,9,'thirty',1,2,3,4,5,6,7,8,9,'forty',1,2,3,4,5,6,7,8,9,'fifty',1,2,3,4,5,6,7,8,9,'sixty',1,2,3,4,5,6,7,8,9,70,1,2,3,4,5,6,7,8,9,80]"; | |
allPassed &= tools.assert(crazy + ' -> ' + flatcrazy, tools.isEqual(eval(flatcrazy), tools.flatten(eval(crazy)))); | |
//test that it fails too | |
allPassed &= tools.assert('[1,2,3] <> ' + crazy, !tools.isEqual([1,2,3], tools.flatten(eval(crazy)))); | |
//extra crazy | |
crazy = eval(crazy); | |
flatcrazy = eval(flatcrazy); | |
crazy = [crazy,[crazy, crazy], crazy, [[flatcrazy]]]; | |
flatcrazy = flatcrazy.concat(flatcrazy,flatcrazy,flatcrazy,flatcrazy); | |
allPassed &= tools.assert('extra crazy', tools.isEqual(flatcrazy, tools.flatten(crazy))); | |
// test that objects, don't confuse it | |
allPassed &= tools.assert('{ one:[1], two:[2], three:[3]} <> [1,2,3]', !tools.isEqual({ one:[1], two:[2], three:[3]},[1,2,3])); | |
allPassed &= tools.assert('[{one:1,two:2,three:3}] <> [1,2,3]', !tools.isEqual([{one:1,two:2,three:3}],[1,2,3])); | |
allPassed &= tools.assert('[{one:1,two:2,three:3}] -> [{one:1,two:2,three:3}]', !tools.isEqual([{one:1,two:2,three:3}],[{one:1,two:2,three:3}])); | |
//test empty arrays | |
var empty = '[[[[[[[[[[[[[[[[[[[[]]]]]]]]]]]]]]]]]]]]'; | |
allPassed &= tools.assert('[] -> ' + empty, tools.isEqual([], tools.flatten(eval(empty)))); | |
if (allPassed) console.log("Yay! All selftests passed!"); | |
return allPassed; | |
} | |
} | |
tools.selfTest(); | |
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