Reading documentation when examples assume concepts the learner has not met yet

I open documentation for a JavaScript library and the first example already assumes I understand promises, modules and several build tools. I'm trying to solve one small problem, but every paragraph sends me to another unfamiliar concept. How do you read docs productively at that stage? I'm tempted to reproduce the smallest working example, then trace only the unfamiliar pieces that directly affect it instead of attempting a full prerequisite course first.