# nlohmann::basic_json::operator<=
```cpp
// until C++20
bool operator<=(const_reference lhs, const_reference rhs) noexcept; // (1)
template
bool operator<=(const_reference lhs, const ScalarType rhs) noexcept; // (2)
template
bool operator<=(ScalarType lhs, const const_reference rhs) noexcept; // (2)
```
1. Compares whether one JSON value `lhs` is less than or equal to another JSON value `rhs`
according to the following rules:
- The comparison always yields `#!cpp false` if (1) either operand is discarded, or (2) either
operand is `NaN` and the other operand is either `NaN` or any other number.
- Otherwise, returns the result of `#!cpp !(rhs < lhs)` (see [**operator<**](operator_lt.md)).
2. Compares whether a JSON value is less than or equal to a scalar or a scalar is less than or equal
to a JSON value by converting the scalar to a JSON value and comparing both JSON values according
to 1.
## Template parameters
`ScalarType`
: a scalar type according to `std::is_scalar::value`
## Parameters
`lhs` (in)
: first value to consider
`rhs` (in)
: second value to consider
## Return value
whether `lhs` is less than or equal to `rhs`
## Exception safety
No-throw guarantee: this function never throws exceptions.
## Complexity
Linear.
## Notes
!!! note "Comparing `NaN`"
`NaN` values are unordered within the domain of numbers.
The following comparisons all yield `#!cpp false`:
1. Comparing a `NaN` with itself.
2. Comparing a `NaN` with another `NaN`.
3. Comparing a `NaN` and any other number.
!!! note "Operator overload resolution"
Since C++20 overload resolution will consider the _rewritten candidate_ generated from
[`operator<=>`](operator_spaceship.md).
## Examples
??? example
The example demonstrates comparing several JSON types.
```cpp
--8<-- "examples/operator__lessequal.cpp"
```
Output:
```json
--8<-- "examples/operator__lessequal.output"
```
## See also
- [**operator<=>**](operator_spaceship.md) comparison: 3-way
## Version history
1. Added in version 1.0.0. Conditionally removed since C++20 in version 3.11.0.
2. Added in version 1.0.0. Conditionally removed since C++20 in version 3.11.0.