It's called "confidence". Investors will let go of their dollars when they feel there's a reasonable expectation of return. This creates jobs as businesses receive the added boost of money that allows them to produce more goods and products to service the economy. Also, small businesses that may not be directly tied to the stock market will benefit from this atmosphere of business confidence and will likewise be able to hire new workers. You can never legislate economic success.
I agree that confidence is a factor and that there was a confidence bump when Trump got elected.
However, you must also agree that the economy was pretty confident under Obama too. Right now, it's the highest it's been since 2008 but in 2015, that could also be said. Similarly, the unemployment rate was the lowest it's been in 2016, before it went lower in 2017.
I also distinctly recall Republicans disparaging both successss under Obama. The stock market doesn't reflect the rest of the economy, they said! The unemployment numbers don't show all the people who've dropped out of the workforce, they complained.
I was struck by how the Republican party had to paint a negative, dark picture of America even when signs of success and hope were available. I am glad that they are able to, once again, see the good in America, despite nothing significantly different happening in the economy. It is simply the same growth, just under different management. Apparently making America great again was simply a matter of changing perspective.