A language agnostic code syntax highlighter in React.

This module is just a function that takes two parameters:

• The source code of type string
• Object needed to style parts of the source code of type object
• Characther list of type object

and returns an array of React span components.

This object should contain two types of values:

• tokens
• sub-routines

these values should be given a css styles object.

tokens

tokens are strings of characters that are not within a certain list of characters.

the default list contains these characters:

+ - * " ' ` / ( ) [ ] { } & ^ % $ ~ # (\n new line character)
! ; . ? < > : \ , | = (\s space character) (\t tab character)

this list can be changed by passing a new character list as a third parameter to the function

an example for js:

  "new":{color:"rgb(225,135,245)"},
  "return":{color:"rgb(225,135,245)"},
  "if":{color:"rgb(225,135,245)"},
  "for":{color:"rgb(225,135,245)"},
  "else":{color:"rgb(225,135,245)"},
  "let":{color:"rgb(100,180,250)"},
  "const":{color:"rgb(100,180,250)"},
  "of":{color:"rgb(100,180,250)"},
  "function":{color:"rgb(100,180,250)"},

sub-routines

sub-routines are just funtions that capture tokens or characters that satisfy the conditions of that function.

so far there are only 5 sub-routines:

• /number/: captures any string-pattern that is a number including hex numbers.
• /before/: captures a token that comes before a given token.
• /after/: captures a token that comes after a given token.
• /patterns/ : captures any given string-pattern.
• /ranges/: captures characters in between two given patterns.

an example for js:

 "/number/":{color:"#aef2ae"},
 // functions and function calls
  "/before/":{
       "(":{color:"rgb(220,220,100)",fontWeight:"900"},
  },
  "/after/":{
       "const":{color:"rgb(100,210,250)"},
  },
  "/patterns/":{
        "=>": {color:"rgb(100,180,250)"},
        "+" : {color:"white"},
        "=" : {color:"white"},
        "-" : {color:"white"},
        ";" : {color:"white"},
        "{" : {color:"rgb(100,180,250)"},
        "}" : {color:"rgb(100,180,250)"},
        "(" : {color:"rgb(100,180,250)"},
        ")" : {color:"rgb(100,180,250)"},
        "[" : {color:"rgb(100,180,250)"},
        "]" : {color:"rgb(100,180,250)"},
  },
  "/ranges/":[
     { // string
        start:['"'],
        end:[['"']],
        style:{color:"#fa9866"}, 
        patterns:{'\\"':{color:"rgb(255, 214, 99)"},} 
    },
    
    { // template literal:
        start:["`"],
        end:[["`"]],
        style:{color:"#fa9866"},
        "/ranges/":[
            {
              start:["${",{color:"rgb(90,100,250)"}],
              end:[["}",{color:"rgb(90,100,250)"}]],
              style:"self"
            }
        ],
    },
    // comments
    {start:["/*"], end:[["*/"]], style:{color:"rgb(180,240,190)"}},
    {start:["//"], end:[["\n"]], style:{color:"rgb(180,240,190)"}},
  ],

A bit more on ranges

ranges should be an array of objects and those objects can have 5 values:

• start
• end
• style
• ranges
• patterns

start: is the start pattern of the range and should be an array of 2 values:

• string-pattern
• styles object

if the second index is empty then the style value will be used by default.

end: is the end pattern of the range and should be an array of arrays that can contain any amount of the same array that start uses, that way the range can stop at any one of those patterns given to end.

style: styles object that styles whatever is in between start and end, but can also be a string called "self" which will recursively style the range with the previously mentioned styles.

ranges: a sub-range of a range.

patterns: captures any string-pattern within the range.

there's also an example and in order to see that example you need to add the script tag below in your html file

<script type="module" src="@arjan32/code-highlighter/Example/example.jsx" defer></script>

and then add a div with the id "ch-example-root"