#### Polynomial

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```/**
* Polynomials are algebraic expressions consisting of two or more algebraic terms.
* Terms of a polynomial are:
* 1. Coefficients e.g. 5, 4 in 5x^0, 4x^3 respectively
* 2. Variables e.g. y in 3y^2
* 3. Exponents e.g. 5 in y^5
*
* Class Polynomial constructs the polynomial using Array as an argument.
* The members of array are coefficients and their indexes as exponents.
*/
class Polynomial {
constructor (array) {
this.coefficientArray = array // array of coefficients
this.polynomial = '' // in terms of x e.g. (2x) + (1)
this.construct()
}

/**
* Function to construct the polynomial in terms of x using the coefficientArray
*/
construct () {
this.polynomial = this.coefficientArray
.map((coefficient, exponent) => {
if (coefficient === 0) {
return '0'
}
if (exponent === 0) {
return `(\${coefficient})`
} else if (exponent === 1) {
return `(\${coefficient}x)`
} else {
return `(\${coefficient}x^\${exponent})`
}
})
.filter((x) =>
x !== '0'
)
.reverse()
.join(' + ')
}

/**
* Function to display polynomial in terms of x
* @returns {String} of polynomial representation in terms of x
*/
display () {
return this.polynomial
}

/**
* Function to calculate the value of the polynomial by substituting variable x
* @param {Number} value
*/
evaluate (value) {
return this.coefficientArray.reduce((result, coefficient, exponent) => {
return result + coefficient * Math.pow(value, exponent)
}, 0)
}
}

export { Polynomial }
```  