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closure.js
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67 lines (53 loc) · 1.62 KB
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// Complete the following functions.
const counter = (number) => {
number+=1;
return number;
// Return a function that when invoked increments and returns a counter variable.
// Example: const newCounter = counter();
// newCounter(); // 1
// newCounter(); // 2
};
const counterFactory = () => {
let binary={
increment:function(number){
return number++;
},
decrement:function(counter){
return counter--;
},
}
return binary;
// Return an object that has two methods called `increment` and `decrement`.
// `increment` should increment a counter variable in closure scope and return it.
// `decrement` should decrement the counter variable and return it.
};
const limitFunctionCallCount = (cb, n) => {
// Should return a function that invokes `cb`.
// The returned function should only allow `cb` to be invoked `n` times.
};
/* STRETCH PROBLEM */
const cacheFunction = (cb) => {
funct(){
cache={
}
if(cache.includes(cb)===true){
return cb;
}else{
cb(cb);
}
cache.cb=cb;
}
// Should return a funciton that invokes `cb`.
// A cache (object) should be kept in closure scope.
// The cache should keep track of all arguments have been used to invoke this function.
// If the returned function is invoked with arguments that it has already seen
// then it should return the cached result and not invoke `cb` again.
// `cb` should only ever be invoked once for a given set of arguments.
};
/* eslint-enable no-unused-vars */
module.exports = {
counter,
counterFactory,
cacheFunction,
limitFunctionCallCount,
};