Import the relevant libraries – redux-deep-diff library uses deep-diff to create diffs and clone-deep to clone the state when traveling through history to prevent mutations; the ngrx-store-freeze library uses deep-freeze to recursively freeze the state.
const diff = require('deep-diff')
const clone = require('clone-deep')
const freeze = require('deep-freeze')
let lhs, rhs, diffs, target
This is a succesful test where freezing, diffing, and cloning the state works as expected.
lhs = freeze({ data: { foo: 'bar', arr: [1, 2, 3] } })
rhs = freeze({ data: { foo: 'baz', arr: [1, 2, 3, 4] } })
diffs = diff(lhs, rhs)
target = clone(rhs)
console.log(target)
diff.revertChange(target, target, diffs[1])
console.log(target)
This is a failing test when part of the state contains a non-pojo. A limitation of deep-clone returns a reference and revertChange attempts to mutate the target.
class Obj {
constructor(props) {
Object.assign(this, props)
}
}
lhs = freeze({ data: new Obj({ foo: 'bar', arr: [1, 2, 3] }) })
rhs = freeze({ data: new Obj({ foo: 'baz', arr: [1, 2, 3, 4] }) })
diffs = diff(lhs, rhs)
target = clone(rhs)
console.log(target)
diff.revertChange(target, target, diffs[1])
console.log(target)
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