Posts

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Git – You’re Doing It Wrong

Instead ofDo this
git checkout {file}git restore {file}
git checkout {branch}git switch {branch}
git checkout -b {newbranch}git switch -c {newbranch}
git push --forcegit push --force-with-lease
git rebasegit rebase --update-refs

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How to make Firefox auto-suggest “shortcut URLs”

I use both gmail.com (redirects to mail.google.com) and rmilk.com (redirects to rememberthemilk.com) all the time as shortcuts. Chrome “remembers” this and as soon as I type “gm” or “rm” it is auto-suggesting them and I just hit enter to get where I want to be.

I just switched back to Firefox (ublock origin forever!) and it massively down-rates URLs that redirect in its “what to auto-suggest” algorithm. You can tweak this, though, by putting `about: config` into the URL bar and setting `places.frecency.permRedirectVisitBonus` and `places.frecency.redirectSourceVisitBonus` to 2000 over their initial low values.

firefox-source-docs.mozilla.org/browser/urlbar/ranking.html has all the gory details and more.
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Nord Light Theme

I like my terminal to change theme when I ssh into another machine. I have been using Solarized Light and Solarized Dark to facilitate this for some time. But now I have gotten hooked on Nord which has no light version. So I made one, just for Terminal for now at least.

Screenshot of Nord Light theme with colored ls output

There are notes about a “bright ambiance” version of the theme in the Nord docs but no actual themes available. The official Terminal.app theme actually deviates from the core 16-color palette but I didn’t do that here. I just chose the most appropriate color from the 16 color palette for each option in a Terminal theme.

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Avoid trailing comma when emitting lists in Mustache templates

In pure Mustache there’s no (simple) way to avoid a trailing comma on a list:

{{#items}}{{.}}, {{/items}}

Which produces something like: “First, Second, Third, “

There are various ways around this. If you’re working in HTML I think the nicest is to model your list as an actual HTML list and use CSS:

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8"/>
    <title>Lists</title>
    <style>
      .list {           
        margin: 0;      
        padding: 0;
      }
      .list li {           
        display: inline;             
      }
      .list li:not(:last-child):after {
        content: ", ";               
      }
    </style>
  </head>
  <body>
    <ol class="list">
      <li>First</li>
      <li>Second</li>
      <li>Third</li>
    </ol>
  </body>
</html>

Which produces: “First, Second, Third”.

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Python types for a decorator that is agnostic about the wrapped func’s return type


import random
from typing import Callable, ParamSpec, TypeVar

T = TypeVar("T")
P = ParamSpec("P")

def some_global_condition() -> bool:
    return random.choice([True, False])

def my_return_type_preserving_decorator(val: T) -> Callable[[Callable[P, T]], Callable[P, T]]:
    def decorator(func: Callable[P, T]) -> Callable[P, T]:
        def wrapper(*args: P.args, **kwargs: P.kwargs) -> T:
            if some_global_condition():
                return val
            return func(*args, **kwargs)
        return wrapper
    return decorator

@my_return_type_preserving_decorator((True, True, True))
def my_func(n: int) -> tuple[bool, bool, bool]:
    return n > 10, n > 100, n > 1000

x = my_func(5)
for r in x:
    print("yes" if r else "no")
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Format Percentage for Display in JavaScript

Input Output
0.12 12%
0.0012345 0.12%
0.0 0

2 significant digits but locale-sensitive, strip meaningless trailing zeroes and decimal dividers.

const formatPercentage = function (value) {
    return new Intl.NumberFormat(
        undefined, // use browser locale
        // Choose the options that get us closest to our desired style – a percentage that tells you enough to be useful but no unnecessary decimal places or trailing zeroes.
        {
            style: "percent", // Treat decimals as percentages, multiplying by 100 and adding a % sign.
            minimumSignificantDigits: 2,
            maximumSignificantDigits: 2
        }
    )
        .format(value)
        // \D here is the locale-agnostic decimals separator.
        .replace(/(\D[0-9]*?)0+%$/, "$1%") // Get rid of trailing zeroes after the decimal separator.
        .replace(/\D%/, "%") // Clean up the scenario where we got rid of everything after the decimal separator and now have something like "4.%.
        .replace(/^0%$/, "0"); // Replace literal "0%" with "0" as zero is unitless.
};
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Python Types for Union of String Literal and Other Type

I wanted to add a single special value to another type for a union type, something like this:

from typing import Literal
                                                                            
UNMEASURED = "unmeasured"                                                    
Unmeasured = Literal[UNMEASURED]
Resource = int | Unmeasured

notes: dict[Resource, str] = {1: "foo", 2: "bar", 3: "baz", UNMEASURED: "quux"}
resources = [1, 2, 3] + [UNMEASURED]
for resource in resources:
    print(notes[resource])

This works, but mypy complains: ‘error: Parameter 1 of Literal[…] is invalid [valid-type]’. So to make this pass mypy typechecking you have to repeat “unmeasured” as a literal. Even if you do that:

from typing import Literal

UNMEASURED = "unmeasured"
Unmeasured = Literal["unmeasured"]
Resource = int | Unmeasured

notes: dict[Resource, str] = {1: "foo", 2: "bar", 3: "baz", UNMEASURED: "quux"}
resources = [1, 2, 3] + [UNMEASURED]
for resource in resources:
    print(notes[resource])

mypy will complain: ‘Dict entry 3 has incompatible type “str”: “str”; expected “int | Literal[‘unmeasured’]”: “str” [dict-item]’ and also ‘Invalid index type “str | int” for “dict[int | Literal[‘unmeasured’], str]”; expected type “int | Literal[‘unmeasured’]” [index]’

Eventually I came up with:

from enum import Enum
from typing import Literal

class Aspect(Enum):
    UNMEASURED = "unmeasured"

Resource = int | Aspect

notes: dict[Resource, str] = {1: "foo", 2: "bar", 3: "baz", Aspect.UNMEASURED: "quux"}
resources = [1, 2, 3] + [Aspect.UNMEASURED]
for resource in resources:
    print(notes[resource])

which both produces the same result, and passes the typechecker. I don’t love the weird Enum hanging out on its own but it does at least put the magic string in one place only and pass. I wonder what would be better.