How to search frontmatter with dataviewjs?

[pppaapp]

---
created: 2022-09-19 23:19:17
tags: a b c d
qwerty: 
  banana: monkey
  honey: bee
---

asdasdasd

there's a note like this

table file.tags
from "20 - Zettelkasten"
where file.frontmatter.qwerty.banana = "monkey"

dv.table(["1", "2"],
dv.pages("")
    .filter(b => b.file.path.includes("20 - Zettelkasten"))
    .where(b => b.file.frontmatter.qwerty.banana = "monkey")
	.map(b => [b.file.link, b.file.tags]))

and there are two dataview

but dataviewjs is in an error.....

how do I fix it?

[AB1908]

Comparisons are == and not =.

[pppaapp]

Comparisons are == and not =.

i modified it
but....

[BrianHicks]

I bet it's looking at other files in "20 - Zettelkasten" that have frontmatter but not that specific path. Since they don't, and you're trying to look it up in JavaScript, you're trying to access stuff on undefined structures. It might work to use the ?. operator, which will short-circuit if it encounters a value like this. So you'd be looking at something like b.file.frontmatter.qwerty?.banana == "monkey". If that operator isn't supported (I don't remember off the top of my head) you can do b.file.frontmatter.qwerty && b.file.fontmatter.qwerty.banana == "monkey")