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The serde-json-fmt crate lets you create custom serde_json formatters with the indentation, separators, and ASCII requirements of your choice.

serde_json itself only directly provides the ability to produce JSON in either "compact" form or "pretty" form, with the only customizable aspect being the string used for pretty indentation. serde-json-fmt complements serde_json to let you also customize the whitespace around commas & colons and whether to escape non-ASCII characters.

Installation

serde-json-fmt requires version 1.60 of Rust or higher. To use the serde-json-fmt library in your Cargo project, add the following to your Cargo.toml:

toml [dependencies] serde-json-fmt = "0.1.0"

Examples

Say you want to serialize a value in one-line "compact" form, but you want a space after each colon & comma, something that serde_json's compact form doesn't do. serde-json-fmt lets you do that:

```rust use serdejson::json; use serdejson_fmt::JsonFormat;

let value = json!({ "colors": ["red", "blue", "taupe"], "sub": { "name": "Foo", "on": true, "size": 17 } });

let s = JsonFormat::new() .comma(", ") .unwrap() .colon(": ") .unwrap() .formattostring(&value) .unwrap();

assert_eq!( s, r#"{"colors": ["red", "blue", "taupe"], "sub": {"name": "Foo", "on": true, "size": 17}}"# ); ```

Say you want to format a value in multiline "pretty" form, but using four-space indents and with all non-ASCII characters encoded as \uXXXX escape sequences. serde-json-fmt lets you do that:

```rust use serdejson::json; use serdejson_fmt::JsonFormat;

let value = json!({ "emojis": { "goat":"🐐", "pineapple": "🍍", "smile": "😀", }, "greek": { "α": "alpha", "β": "beta", "γ": "gamma", } });

let s = JsonFormat::pretty() .indentwidth(Some(4)) .ascii(true) .formatto_string(&value) .unwrap();

assert_eq!(s, r#"{ "emojis": { "goat": "\ud83d\udc10", "pineapple": "\ud83c\udf4d", "smile": "\ud83d\ude00" }, "greek": { "\u03b1": "alpha", "\u03b2": "beta", "\u03b3": "gamma" } }"#); ```