Notes

/*
Write a function which reverses the passed string
*/

const reverseString = (str) => {
if(str==''){
return str;
}
return str.split('').reverse().join('');
}

/*
Write a function which removes the passed delimiter from the string.
e.g. 'a-b-c'.removeDelimiter('-') should return 'abc'
*/

String.prototype.removeDelimiter = function(delimiter) {
return this.split(delimiter).join('');
};

/*
Write a function which return the multiplication of three numbers.
The function can be called in any of the following forms:

multiply(2, 3, 4) => 24
multiply(2, 3)(4) => 24
multiply(2)(3, 4) => 24
multiply(2)(3)(4) => 24
*/

let curry = (fn) => {
return function curryFn(...args1) {
if (args1.length >= fn.length) {
return fn(...args1);
} else {
return (...args2) => curryFn(...args1, ...args2);
}
}
}

function product(x,y,z) {
return x*y*z;
}

const multiply = curry(product);

/*
write a function to check if the two object passed are equal or not.
the objects can be nested.
*/

const areEqualObjs = (obj1, obj2) => {
return JSON.stringify(obj1) === JSON.stringify(obj2)
}

/*
write a function to faltten the array
*/

Array.prototype.flatten = function() {
return this.reduce(function (flat, toFlatten) {
return flat.concat(Array.isArray(toFlatten) ? toFlatten.flatten() : toFlatten);
}, []);
};


//Tests

describe('reverseString', () => {
it('reverses the passed string', () => {
expect(reverseString('')).toBe('');
expect(reverseString('abcde')).toBe('edcba');
});
});

describe('removeDelimiter', () => {
it('removes the passed delimiter from the string', () => {
expect(reverseString('')).toBe('');
expect("Equal-Experts".removeDelimiter('-')).toEqual('EqualExperts');
});
});

describe('multiply', () => {
it('curries the multiply for three arguments', () => {
expect(multiply(2, 3, 4)).toBe(24);
expect(multiply(2, 3)(4)).toBe(24);
expect(multiply(2)(3, 4)).toBe(24);
expect(multiply(2)(3)(4)).toBe(24);
});
});

describe('areEqualObjs', () => {
it('compares the objects', () => {
expect(areEqualObjs({
a: 1,
b: 2
}, {
a: 1,
b: 2
})).toBeTruthy();

expect(areEqualObjs({
a: 1,
b: 2
}, {
a: 1,
b: 3
})).toBeFalsy();

expect(areEqualObjs({
a: 1,
b: 2
}, {
a: 1
})).toBeFalsy();

expect(areEqualObjs({
a: {
b: 1
}
}, {
a: {
b: 1
}
})).toBeTruthy();

expect(areEqualObjs({
a: {
b: 1
}
}, {
a: {
b: 2
}
})).toBeFalsy();

expect(areEqualObjs({
a: {
b: 1,
c: {
d: 2
}
}
}, {
a: {
b: 1,
c: {
d: 3
}
}
})).toBeFalsy();

expect(areEqualObjs({
a: {
b: 1,
c: {
d: {
e: 2
}
}
}
}, {
a: {
b: 1,
c: {
d: {
e: 2
}
}
}
})).toBeTruthy();
})
});

describe('flattenArray',() => {
it('flattens the passed array', () => {
expect([].flatten()).toEqual([]);
expect([1, 2].flatten()).toEqual([1, 2]);
expect([1, [2]].flatten()).toEqual([1, 2]);
expect([1, [2, 3]].flatten()).toEqual([1, 2, 3]);
expect([[1], [2], [3], [4], [5]].flatten()).toEqual([1, 2, 3, 4, 5]);
expect([1, 2, [3, [4, 5, 6]], [7, 8]].flatten()).toEqual([1, 2, 3, 4, 5, 6, 7, 8]);
expect([1, [2, [3, [4, [5, [6, [7, [8]]]]]]]].flatten()).toEqual([1, 2, 3, 4, 5, 6, 7, 8]);
});
});