handlebars_misc_helpers
A collection of helpers for handlebars (rust) to manage string, json, yaml, toml, path, file, http request.
Helpers extend the template to generate or to transform content. Few helpers are included, but if you need more helpers, ask via an issue or a PR.
To use an helper:
// arguments are space separated
{{ helper_name arguments}}
To chain helpers, use parenthesis:
{{ to_upper_case (to_singular "Hello foo-bars") }}
// -> BAR
{{ first_non_empty (unquote (json_str_query "package.edition" (read_to_str "Cargo.toml") format="toml")) (env_var "MY_VERSION") "foo" }}
// -> 2018
see Handlebars templating language
String transformation
helper signature | usage sample | sample out |
---|---|---|
replace s:String from:String to:String |
replace "Hello old" "old" "new" |
"Hello new" |
to_lower_case s:String |
to_lower_case "Hello foo-bars" |
"hello foo-bars" |
to_upper_case s:String |
to_upper_case "Hello foo-bars" |
"HELLO FOO-BARS" |
to_camel_case s:String |
to_camel_case "Hello foo-bars" |
"helloFooBars" |
to_pascal_case s:String |
to_pascal_case "Hello foo-bars" |
"HelloFooBars" |
to_snake_case s:String |
to_snake_case "Hello foo-bars" |
"hello_foo_bars" |
to_screaming_snake_case s:String |
to_screaming_snake_case "Hello foo-bars" |
"HELLO_FOO_BARS" |
to_kebab_case s:String |
to_kebab_case "Hello foo-bars" |
"hello-foo-bars" |
to_train_case s:String |
to_train_case "Hello foo-bars" |
"Hello-Foo-Bars" |
to_sentence_case s:String |
to_sentence_case "Hello foo-bars" |
"Hello foo" bars |
to_title_case s:String |
to_title_case "Hello foo-bars" |
"Hello Foo Bars" |
to_class_case s:String |
to_class_case "Hello foo-bars" |
"HelloFooBar" |
to_table_case s:String |
to_table_case "Hello foo-bars" |
"hello_foo_bars" |
to_plural s:String |
to_plural "Hello foo-bars" |
"bars" |
to_singular s:String |
to_singular "Hello foo-bars" |
"bar" |
trim s:String |
trim " foo " |
"foo" |
trim_start s:String |
trim_start " foo " |
"foo " |
trim_end s:String |
trim_end " foo " |
" foo" |
unquote s:String |
unquote "\"foo\"" |
"foo" |
enquote symbol:String s:String |
enquote "" "foo" |
"\"foo\"" |
first_non_empty s:String+ |
first_non_empty "" null "foo" "bar" |
"foo" |
Http content
Helper able to render body response from an http request.
helper signature | usage sample |
---|---|
http_get url:String |
http_get "http://hello/..." |
gitignore_io templates:String |
gitignore_io "rust,visualstudiocode" |
Path extraction
Helper able to extract (or transform) path (defined as string).
for the same input: "/hello/bar/foo.txt"
helper_name | sample output |
---|---|
file_name | "foo.txt" |
parent | "/hello/bar" |
extension | "txt" |
File
Helper to read file content.
usage | output |
---|---|
{{ read_to_str "/foo/bar" }} |
content of file /foo/bar |
{{ read_to_str "file/does/not/exist" }} |
empty string |
Environment variable
Helper able to get environment variables.
helper_name | usage |
---|---|
env_var | env_var "HOME" |
Specials environment variables are predefined (some of them come from std::env::consts - Rust):
JSON & YAML & TOML
helpers:
json_query query:String data:Json
: Helper able to extract information from json using JMESPath syntax forquery
.json_str_query query:String data:String
: Helper able to extract information from json using JMESPath syntax forquery
, data follows the requestedformat
.json_to_str data:Json
: convert a json data into a string following the requestedformat
.str_to_json data:String
: convert(parse) a string into a json following the requestedformat
.
The optional requested format
, is the format of the string with data:
"json"
(default if omitted)"json_pretty"
json with indentation,..."yaml"
"toml"
"toml_pretty"
usage | output |
---|---|
{{ json_query "foo" {} }} |
`` |
{{ json_to_str ( json_query "foo" {"foo":{"bar":{"baz":true}}} ) }} |
{"bar":{"baz":true}} |
{{ json_to_str ( json_query "foo" (str_to_json "{\"foo\":{\"bar\":{\"baz\":true}}}" ) ) }} |
{"bar":{"baz":true}} |
{{ json_str_query "foo" "{\"foo\":{\"bar\":{\"baz\":true}}}" }} |
{"bar":{"baz":true}} |
{{ json_str_query "foo.bar.baz" "{\"foo\":{\"bar\":{\"baz\":true}}}" }} |
true |
{{ json_str_query "foo" "foo:\n bar:\n baz: true\n" format="yaml"}} |
bar:\n baz: true\n |
{{ json_to_str ( str_to_json "{\"foo\":{\"bar\":{\"baz\":true}}}" format="json") format="yaml"}} |
foo:\n bar:\n baz: true\n |
Block
[foo.bar] baz = true
Note: YAML & TOML content are used as input and output format for json data. So capabilities are limited to what json support (eg. no date-time type like in TOML).
Assign
Helper able to assign (to set) a variable to use later in the template.
usage | output |
---|---|
{{ assign "foo" "{}" }} |
`` |
{{ assign "foo" "{}" }}{{ foo }} |
{} |
{{ assign "foo" "hello world" }}{{ foo }} |
hello world |
{{ assign "foo" {} }}{{ foo }} |
[object] |
{{ assign "foo" {"bar": 33} }}{{ foo }} |
[object] |