Question

50

Replace array entry with spread syntax in one line of code?

rated 0 times [ 54] [ 4] / answers: 1 / hits: 40799 / 7 Years ago, mon, august 14, 2017, 12:00:00

I'm replacing an item in a react state array by using the ... spread syntax. This works:

let newImages = [...this.state.images]

newImages[4] = updatedImage

this.setState({images:newImages})

Would it be possible to do this in one line of code? Something like this? (this doesn't work obviously...)

this.setState({images: [...this.state.images, [4]:updatedImage})

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tiffany

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1 Year ago

answered 7 Years ago collinisaaka · Accepted Answer

use Array.slice

this.setState({

  images: [

    ...this.state.images.slice(0, 4),

    updatedImage,

    ...this.state.images.slice(5),

  ],

});

Edit from original post: changed the 3 o a 4 in the second parameter of the slice method since the second parameter points to the member of the array that is beyond the last one kept, it now correctly answers the original question.