Comments (2)
When ignoreIfNoChange is true, setProp() is called early with the input object (which is not the copy and is frozen), and its return value is compared with input object using ===. If no change occurred, iassign() can return early, improving performance.
There are two options to solve your problem:
- Use getProp() to the extract the exact property you want to set (preferred):
var map2 = iassign(
map1,
function (m) { return m.b; },
function (b) { return 50; }
);
- Use Object.assign() to do the manual copy
var map2 = iassign(
map1,
function (m) { return Object.assign({}, m, { b: 50 }); }
);
You should use ignoreIfNoChange if you don't know if the setProp() will update your object or not, e.g., a reducer calling another reducer:
function AppReducer(state, action) {
state = iassign(
state,
function(s) { return s.count; },
function(c) { return CountReducer(c, action); },
undefined, // no context
{ ignoreIfNoChange: true });
return state;
}
function CountReducer(count, action) {
switch (action.type) {
{
case "INCREMENT": count++; break;
case "DECREMENT": count--; break;
}
return count; // it will not change on other actions.
}
from immutableassign.
That sounds reasonable. Thanks!
from immutableassign.
Related Issues (20)
- Module "immutable-assign" has no default export. HOT 5
- iassign does not work correctly with ES6 Map HOT 2
- Error when using bracket notation to access property in getProp HOT 2
- Return the existing object when the value being set hasn't changed HOT 1
- Add a function to only freeze (if enabled) HOT 6
- How to handle possibly null values in getProp? HOT 5
- Proxy polyfill not applied on iOS 9.0 / Android 6.0 HOT 3
- typescript types for immutable-assign HOT 6
- Does not work with create-react-app HOT 1
- Unexpected behavior when Proxy === undefined HOT 2
- Feature request: Allow specifying the path of property to update by an array HOT 2
- How does this compare to immer? HOT 2
- Unexpected behaviour when console.log-ing or using lodash/fp/find HOT 3
- An in-range update of coveralls is breaking the build 🚨 HOT 1
- Nicer API HOT 8
- Support classes HOT 2
- ES6 arrow functions without the `return` keyword don't work as getProp HOT 2
- Provide initialization method HOT 2
- Cannot assign freeze property HOT 3
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from immutableassign.