how to use immutability-helper remove elements from array

var state = [{name:'a'},{name:'b'},{name:'c'},{name:'d'}];
var indexToRemove = state.findIndex(item => item.name === 'c');
var newState = update(state, {$splice: [[indexToRemove, 1]]});
console.log(newState); // [{name: "a"}, {name: "b"}, {name: "d"}]```


if i have a list  var list=['a','c'],
how to remove two elements from array 'state' 

[gnapse]

@joelcollinsdc my first instinct when reading your message was that perhaps it makes sense, and I was almost starting to make a PR to propose the new command, when I realized is not that simple.

$push is a lot simpler, it always works by appending items at the end of the array. A potential $delete action would raise some questions: would it let remove by index? Or by value? If it’s by value, would it remove all occurrences of that value in the array? I’m not saying it can’t be done, I’m just saying there’s no way to satisfy every different need, there are a few different ways in which to approach removing items from an array.

Perhaps the simplest approach, without bloating the set of commands this library provide, is to use the $apply command to provide a function that specifically address what’s needed in each case, describing the state transformation one wants to achieve. And it becomes even simpler with the new shorthand notation for $apply. The $splice command is still useful in some cases of deletion as well:

// Delete a value (7) if found, all occurrences
update(state, {
  items: arr => arr.filter(item => item != 7),
})

// Delete a value (7) if found, first occurrence only
const index = state.items.indexOf(7);
if (index >= 0) {
  update(state, { items: { $splice: [[index, 1]] } });
}

// Delete at a specific index, no matter what value is in it
update(state, { items: { $splice: [[index, 1]] } });

As you see none of these are that complex to merit its own command, and they’re all valid criteria for deleting, depending on the situation at hand. These differences make a generic $delete command difficult to incorporate.

Finally, if you really need this command, in the form of one of the cases described above, several times in your app, you can always declare custom commands.

[GaddMaster]

Would be nice to see any giant list of all sorts of examples. I’m always struggling with the library. Is there one