In TypeScript, combining the numbers 0 and 1 results in the value 01

Question

In TypeScript, combining the numbers 0 and 1 results in the value 01

I am in the process of developing a Shopping Card feature.

private _card: Map<Product, number> = new Map<Product, number>();

...

addToCard(prod: Product, amount: number = 1): void {
    const totalAmount: number = this._card.get(prod) + amount; // Calculating the total amount
    console.log(this._card.get(prod) + ' + ' + amount);
    this._card.set(prod, totalAmount);
  }

Log:

card.service.ts:31 0 + 1
card.service.ts:31 01 + 1
card.service.ts:31 011 + 2
card.service.ts:31 0112 + 2
card.service.ts:31 01122 + 3
card.service.ts:31 011223 + 4

It seems that instead of performing normal addition, the result is being concatenated. I have verified that all variables are declared as numbers.

Thank you for any assistance provided.

angular typescript

Answer 1

Answer №1

If you want to increase the card value by a certain amount, you can simply convert the card value into a number and then add the specified amount

addToCard(prod: Product, amount: number = 1): void {
    const a: number = +this._card.get(prod) + +amount; // Calculating the new total
    console.log(this._card.get(prod) + ' + ' + amount);
    this._card.set(prod, a);
}

Answer 2

If you want to increase the card value by a certain amount, you can simply convert the card value into a number and then add the specified amount

addToCard(prod: Product, amount: number = 1): void {
    const a: number = +this._card.get(prod) + +amount; // Calculating the new total
    console.log(this._card.get(prod) + ' + ' + amount);
    this._card.set(prod, a);
}

Answer 3

Answer №2

let sum:number = parseInt(this._card.get(prod), 10) + parseInt(amount, 10);

To ensure both values are treated as numbers, consider using parseInt with a strict base of 10.

Another alternative is to try:

 let sum:number = this._card.get(prod) += amount;

It's possible that one of the variables, such as prod, is mistakenly being interpreted as a string, leading to concatenation instead of addition.

Answer 4

let sum:number = parseInt(this._card.get(prod), 10) + parseInt(amount, 10);

To ensure both values are treated as numbers, consider using parseInt with a strict base of 10.

Another alternative is to try:

 let sum:number = this._card.get(prod) += amount;

It's possible that one of the variables, such as prod, is mistakenly being interpreted as a string, leading to concatenation instead of addition.

Answer 5

Answer №3

The rationale behind this issue is that calling this._card.get(cord) retrieves a string value, but you can easily modify it as shown below:

addToCart(product: Product, quantity: number = 1): void {
    const totalQuantity: number = +this._cart.get(product) + quantity; // Adding the current quantity with new items
    console.log(this._cart.get(product) + ' + ' + quantity);
    this._cart.set(product, totalQuantity);
  }

Answer 6

The rationale behind this issue is that calling this._card.get(cord) retrieves a string value, but you can easily modify it as shown below:

addToCart(product: Product, quantity: number = 1): void {
    const totalQuantity: number = +this._cart.get(product) + quantity; // Adding the current quantity with new items
    console.log(this._cart.get(product) + ' + ' + quantity);
    this._cart.set(product, totalQuantity);
  }

In TypeScript, combining the numbers 0 and 1 results in the value 01

Answer №1

Answer №2

Answer №3

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