cleanup watch methodes

[bekzod]

removes some work from #14571
since then I think root cause might have been fixed

[bekzod]

since meta has assertion for non-object / non-function values

ember.js/packages/ember-metal/lib/meta.js

Line 556 in 76dc4de

assert(`Cannot call \`meta\` on ${typeof obj}`, typeof obj === 'object' || typeof obj === 'function');

IMHO, it is better to assert than be silent to uncover unnecessary/invalid calls of watchKey

[krisselden]

does the assert check for null objects?

[bekzod]

yes

ember.js/packages/ember-metal/lib/meta.js

Line 554 in 76dc4de

assert('Cannot call `meta` on null', obj !== null);

[bekzod]

since peekMeta has assertion for non-object / non-function values, it is better to assert than be silent to uncover invalid calls of unwatchKey

[mmun]

Yes, I agree, though we should check that this doesn't cause any crashes in a few real world apps before it gets into beta. Can you check that ember observer works correctly with this PR?

[bekzod]

will do

[bekzod]

checked in both emberobserver and emberaddons, both working properly and no regression in benchmarks https://cl.ly/441V333w3R3R/results.pdf