Sharepoint - Filter Created in SP REST API

SharePoint REST API endpoints take ISO formatted date string for filtering.

Try using below query for filtering on Date Field:

1. To check greater than 2018/10/05:

https://[tentat]/sites/[site]/Normativo/ComunicacoesDeNegocio/_api/web/lists('e97f928b-34e4-34e2-c2c7-150ea469fac3')/items?$select=ID,Title,Created,QuemLeu/Id&$expand=QuemLeu&$filter=(Created gt datetime'2018-10-05T00:00:00Z')

2. To check greater than or equal to 2018/10/05:

https://[tentat]/sites/[site]/Normativo/ComunicacoesDeNegocio/_api/web/lists('e97f928b-34e4-34e2-c2c7-150ea469fac3')/items?$select=ID,Title,Created,QuemLeu/Id&$expand=QuemLeu&$filter=(Created ge datetime'2018-10-05T00:00:00Z')

Answer For Updated Question:

Add one more IF statement inside if(data.d) like given below:

if(data.d){
    if(new Date(data.d.Created) > new Date("2018-10-05")) {
        console.log("Items is created after '2018-10-05'");
    } else {
        console.log("Items is created before '2018-10-05'");
        //Add your other code here
    }
} 

Add $filter to your query and use Created gt datetime'2018-10-05T00:00:00' or Created gt '2018-10-05'

/_api/web/lists('guid')/items?$select=ID,Title,Created,QuemLeu/Id&$expand=QuemLeu&$filter=Created gt '2018-10-05'

Just add

&$filter=Created gt '2018-10-05'

At the end of your endpoint

For example:

https://[tentat]/sites/[site]/Normativo/ComunicacoesDeNegocio/_api/web/lists('e97f928b-34e4-34e2-c2c7-150ea469fac3')/items('193')?$select=ID,Title,Created,QuemLeu/Id&$expand=QuemLeu&$filter=Created gt '2018-10-05'

Gt operator means "greater than"

And also you can check all operators below:

Lt (less than)

Le (less than or equal)

Gt (greater than)

Ge (greater than or equal)

Eq (equal to)

Ne (not equal to)