JavaScript - Trouble encountered while trying to use splice to insert one array into another array

Question

JavaScript - Trouble encountered while trying to use splice to insert one array into another array

I've been working on creating a Cache Hashtable using JavaScript.

When I use the code cache.splice(0,0, ...dataPage);, it inserts my data starting from the first position up to the length of dataPage.

Assuming that my dataPage size is always 10.

The expected structure of my cache array should be

[0: {..}, 1: {..} ..... 9: {...}]

Now, let's say I need to load the 5th page of data. Upon executing cache.splice(40,0, ...data);,

I anticipate my array to look like

[[0: {..}, 1: {..} ..... 9: {...}, 40: {...}, 41:{...} ... 49{...}]

However, the actual result turns out to be

[[0: {..}, 1: {..} ..... 9: {...}, 10: {...}, 11:{...} ... 12{...}]

Any suggestions on how I can achieve the desired outcome?

javascript arrays typescript

Answer 1

Answer №1

Inserting data at a specific position in a cache

: The code snippet cache.splice(40,0, ...data) indicates that the ...data will be added at the 40th index of the cache.

If the cache does not have 40 elements, the insertion cannot take place at that position.

It might be helpful to first create a cache with the required number of positions and then insert your data using splice.

UPDATE Yes, you can achieve this dynamically. An example could be as follows (this is untested but illustrates the idea):

var cache = [];
var insertion_pos = 40;
var dataPage = [0: {..}, 1: {..} ..... 9: {...}, 10: {...}, 11:{...} ... 12:{...}]

for(var i=0; i < insertion_pos; i++) {
   cache.push(i);
}

cache.splice(insertion_pos, 0, ...dataPage)

Answer 2

Inserting data at a specific position in a cache

: The code snippet cache.splice(40,0, ...data) indicates that the ...data will be added at the 40th index of the cache.

If the cache does not have 40 elements, the insertion cannot take place at that position.

It might be helpful to first create a cache with the required number of positions and then insert your data using splice.

UPDATE Yes, you can achieve this dynamically. An example could be as follows (this is untested but illustrates the idea):

var cache = [];
var insertion_pos = 40;
var dataPage = [0: {..}, 1: {..} ..... 9: {...}, 10: {...}, 11:{...} ... 12:{...}]

for(var i=0; i < insertion_pos; i++) {
   cache.push(i);
}

cache.splice(insertion_pos, 0, ...dataPage)

JavaScript - Trouble encountered while trying to use splice to insert one array into another array

Answer №1

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