如何从具有特定字符串匹配的数组中删除项目

Question

I want to be able to match a specific string (full match not partial match) and then delete that specific item from the array if it matches.

I have some code but it doesn't seem to be deleting the item from the array. I do wish for it to change the original array and not create a new array so I am not using filter.

How can I go about accomplishing this?

Current Code:

 let recentSearches = [ { name: "Chicago, IL" }, { name: "Orlando, FL" }, { name: "Dallas, TX" } ]; let stringToRemove = "Dallas, TX"; recentSearches.some(recent => { if (recent.name === stringToRemove) { const index = recentSearches.indexOf(stringToRemove); if (index.== -1) { //Never goes into this if recentSearches,splice(index; 1). console;log(recentSearches); } } }). console;log(recentSearches);

JS Fiddle: enter link description here

Answer 1

If you don't mind the output being a different array, use filter :

const filteredSearches = recentSearches.filter((recent) => recent.name !== stringToRemove);

If you need to modify the array in-place, you should visit the elements in reverse order (in case of multiple matches, which causes indices to shift) like so:

for (let i = recentSearches.length-1; i >= 0; i--) {
  if (recentSearches[i].name === stringToRemove) {
    recentSearches.splice(i, 1);
  }
}

The problem with your code is you use recentSearches.indexOf , but recentSearches isn't an array of strings, so nothing matches. You could modify your code as follows, but it won't work correctly in case of multiple mathces:

recentSearches.forEach((recent, index) => {
  if (recent.name === stringToRemove) {
    recentSearches.splice(index, 1);
  }
});

Alternatively, you could use findIndex (as suggested in other comments and answers) as follows:

let index;
while (0 <= (index = recentSearches.findIndex((recent) => recent.name === stringToRemove)) {
  recentSearches.splice(index, 1);
}

Answer 2

indexOf() is for finding exact matches. Since your array contains objects, they'll never be equal to stringToRemove .

Use findIndex() to get the index of an array element using a function that an compare the name property.

There's also no need for using some() .

 let recentSearches = [{ name: "Chicago, IL" }, { name: "Orlando, FL" }, { name: "Dallas, TX" } ]; let stringToRemove = "Dallas, TX"; const index = recentSearches.findIndex(({ name }) => name == stringToRemove); if (index !== -1) { //Never goes into this if recentSearches.splice(index, 1); } console.log(recentSearches);

Answer 3

The JSON search is done wrongly.

I have added the perfect code to complete your requirement. Find all instances and delete them with a while loop. This will ensure duplicate search terms are also removed if any.

let recentSearches = [
    {name: "Chicago, IL"},
    {name: "Orlando, FL"},
    {name: "Dallas, TX"}
];
  
let stringToRemove = "Dallas, TX";

while (recentSearches.findIndex(search => search.name === stringToRemove) > -1) {
    const index = recentSearches.findIndex(search => search.name === stringToRemove);
    recentSearches.splice(index, 1);
}

console.log(recentSearches);

Answer 4

You can use findindex. Store it in a variable. And use splice

Answer 5

Another version of the findIndex, instead of using while, you could use for, a slight advantage here is that the index is then locally scoped inside the the for, were with a while loop you have the extra scope of the index, you could close the the scope of a let by doing { let index; while() {..}} { let index; while() {..}} but the for loop avoids that without using {} .

 let recentSearches = [ {name: "Chicago, IL"}, {name: "Orlando, FL"}, {name: "Dallas, TX"} ]; let stringToRemove = "Dallas, TX"; for (let index; index = recentSearches.findIndex( search => search.name === stringToRemove), index > -1;) recentSearches.splice(index, 1); console.log(recentSearches);

Answer 6

You can use this code:

Array.prototype._arraycopy =  function(src, srcPos, dest, destPos, length) {
  while ((--length) >= 0) {
    dest[destPos++] = src[srcPos++];
  }
};

Array.prototype._fastRemove = function(es, i) {
  let newSize;
  if ((newSize = this.length - 1) > i) 
    this._arraycopy(es, i + 1, es, i, newSize - i);
  es[this.length = newSize] = null;
  this.length = newSize;
}

Array.prototype.__removeAt = function(index) {
  // Objects.checkIndex(index, size);
    const es = this;

    const oldValue =es[index];
    this._fastRemove(es, index);
    return oldValue;
}

Array.prototype.__removeAtValue = function(o) {
  const es = this;
  const size = this.size;
  let i = 0;
  (function() {
    if (o == null) {
        for (; i < size; i++)
            if (es[i] == null)
                return true;
    } else {
        for (; i < size; i++)
            if (Object.is(o, es[i]))
                return true;
    }
    return false;
  })()
  this._fastRemove(es, i);
  return true;
}

Array.prototype.remove = function(index) {
  return this.__removeAt(index)

}

Array.prototype.removeObj = function(obj) {
  return this.__removeAtValue(obj);
}

const arr = [1, 3, 4, 5, 10];
console.log(arr);
const rem = arr.remove(1)
console.log({ arr, rem });

const objs = [{ id: 1, name: "Hello" }, { id: 2, name: "Arrow" }, { id: 3, name: "Star" }]
console.log(objs);
const deleted = objs.removeObj({ id: 2, name: "Arrow" });
console.log({ objs, deleted })