Loops/While: Difference between revisions
→A solution in a functional idiom of JavaScript
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=={{header|JavaScript}}==
<lang javascript>var n = 1024;
while (n > 0) {
}</lang>
In a functional idiom of JavaScript, however, we can not use a loop statement to achieve this task, as statements return no value, mutate state, and can not be composed within other functional expressions.
Instead, we can define a composable loopWhile() function which has no side effects, and takes 3 arguments:
:#An initial value
:#A function which returns some derived value
:#A conditional function
<lang JavaScript>function loopWhile(varValue, fnDelta, fnTest) {
'use strict';
var d = fnDelta(varValue);
return fnTest(d) ? [d].concat(
loopWhile(d, fnDelta, fnTest)
) : [d];
}
console.log(
loopWhile(
1024,
function (x) {
return x / 2
},
function (x) {
return x;
}
).join('\n')
);</lang>
=={{header|Joy}}==
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