Ytukyg

I have a variable pointing to an object and would like to replace that object with another modified one. Is there any Javascript function that can do what my hypothetical "assign" function does in the example console session below?

var x = [[1,2,3], [4,[8,2,[1,4,"Delete Me"],4],6]]

var y = getSubArrayWithString(x) // Equivalent to y = x[1][1][2] in this case

JSON.stringify(y)

>>> "[1,4,"Delete Me"]"

var newY = y.filter(item => item !== "Delete Me")

y.assign(newY) // Equivalent to x[1][1][2] = newY

JSON.stringify(x)

>>> "[[1,2,3],[4,[8,2,[1,4],4],6]]"

If I do y = newY that just reassigns the y variable to point at the newY object, it doesn't modify x.

I know I could modify y in place using splice, but that won't work when I'm applying more complex changes to get newY

Ideally getSubArrayWithString() would return a reference to the parent of the array you are interested in modifying (and maybe even the index you want). Then it's easy:

var x = [[1,2,3], [4,[8,2,[1,4,"Delete Me"],4],6]]

var [y, ind] = [x[1][1], 2]  // getSubArrayWithString returns parent and index

y[ind] = y[ind].filter(item => item !== "Delete Me")

console.log(x)

If your really stuck with just the array reference, you can use splice() to alter the array rather than overwrite it. You could even splice() everything and reassign the new values, but this seems pretty inefficient:

var x = [[1,2,3], [4,[8,2,[1,4,"Delete Me"],4],6]]

var y = x[1][1][2]

var newY = y.filter(item => item !== "Delete Me")



y.splice(0,y.length)  // sketchy, but works

Object.assign(y, newY)



console.log(x)