test for null parameter js chai code example

Example 1: chai expect to be type array

expect([1, 2]).to.be.an('array');

Example 2: chai length greater than

expect('foo').to.have.lengthOf(3); // Recommended
expect('foo').to.have.lengthOf.above(2); // Not recommended

expect([1, 2, 3]).to.have.lengthOf(3); // Recommended
expect([1, 2, 3]).to.have.lengthOf.above(2); // Not recommended