Meanings of triumphant declaration in English

Another long pull at the cigarette, and then the triumphant declaration:

Later in the day came a triumphant declaration: Successful build!

At the end of this triumphant declaration, she added-

Minutes before the triumphant declaration, Mr Dillon swept into the count centre, followed, and sometimes shouldered by, some of the hundreds of his supporters.

The image of Romania's communist despot reduced to a crumpled, bloody corpse was beamed across the world, apparently a triumphant declaration of all-out revolution.

Dong-Yung smiled, too, at his open, triumphant declarations.