no-truthy-falsy.md
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toBeTruthy()
& toBeFalsy()
(no-truthy-falsy
)
Disallow using Deprecated
This rule has been deprecated in favor of
no-restricted-matchers
with the following config:
{
"rules": {
"jest/no-restricted-matchers": [
"error",
{
"toBeTruthy": "Avoid `toBeTruthy`",
"toBeFalsy": "Avoid `toBeFalsy`"
}
]
}
}
Tests against boolean values should assert true or false. Asserting toBeTruthy
or toBeFalsy
matches non-boolean values as well and encourages weaker tests.
For example, expect(someBoolean).toBeFalsy()
passes when
someBoolean === null
, and when someBoolean === false
.
Similarly, expect(someBoolean).toBeTruthy()
passes when someBoolean === []
,
and when someBoolean === 'false'
(note that 'false'
is a string).
Rule details
This rule triggers a warning if toBeTruthy()
or toBeFalsy()
are used.
This rule is disabled by default.
Default configuration
The following patterns are considered warnings:
expect(someValue).toBeTruthy();
expect(someValue).toBeFalsy();
The following patterns are not considered warnings:
expect(someValue).toBe(true);
expect(someValue).toBe(false);