If at least one of the values returned from the loop is true, the function must return true. How can I do this?

  const addCart = () => {
    for (let i = 0; i < props.cart.length; i  ) {
      return props.cart[i].domainName === props.domainName;
    }
  };

CodePudding user response：

Try the following code.

const addCart = () => {
  for (let i = 0; i < props.cart.length; i  ) {
    if (props.cart[i].domainName === props.domainName) {
      return true;
    }
  }
  return false;
};

The function returns true when the first equal property has been found. It gives you the possibility to obtain the result without checking all elements of the array.

CodePudding user response：

You can use some here

const addCart = () => {
  if (props.cart.some((o) => o.domainName === props.domainName)) return true;
  return false;
};

or simply using single liner solution

const addCart = () => props.cart.some((o) => o.domainName === props.domainName);

CodePudding user response：

I'd suggest:

const addCart = () => {
  // here we use Array.prototype.some(),
  // which returns a Boolean; true if any
  // of the array-elements match the provided
  // assessment, or false if not:
  return props.cart.some(
    (cart) => cart.domainName === props.domainName
  );
}

References:

• Arrow functions.
• Array.prototype.some().

CodePudding user response：

const addCart = () => props.cart.some(e=>e.domainName===props.domainName);