Observable array should be concat-spreadable

[Zzzen]

I have a*:

2. Issue:

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• Provide as much relevant code, or, preferrably create a reproduction based on this JSFiddle:
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MobX version: 3.1.7
Code:

    var a2 = mobx.observable([3, 4])
    var result = [1, 2].concat(a2)

I expect result to be [1, 2, 3, 4]. But it is [1, 2, ObservableArray]

[spion]

Unfortunately this will cause unexpected behaviour in older browsers (see #806)

[mweststrate]

This is indeed a known limitation until proxies are fully supported. Use a2.slice() instead. Also see the docs.

[vantuan88291]

0

another way to concat array in mobx:

const arr = [...self.data, ...result.data.data.customers]
self.data.replace(arr)