Parse or Tokenize JavaScript code using Esprima

Use the Esprima library to parse or tokenize JavaScript code. Note that the first time this function is called, it will load the esprima library into the JavaScript context, which may take a few seconds. Subsequent calls will be faster.

Usage

esprima_parse(input, options = list(), type = "script")

esprima_tokenize(input, options = list())

Arguments

input: A character string containing the JavaScript code to be parsed or tokenized.
options: A list of configuration options to pass to the Esprima parser or tokenizer.
type: A character string specifying the type of code to parse: "script" (default) or "module".

Value

For esprima_parse, a list representing the Abstract Syntax Tree (AST) of the parsed code. For esprima_tokenize, a list of tokens extracted from the input code.

Examples

js_code <- 'const answer = 42;'
esprima_parse(js_code)
#> $type
#> [1] "Program"
#> 
#> $body
#> $body[[1]]
#> $body[[1]]$type
#> [1] "VariableDeclaration"
#> 
#> $body[[1]]$declarations
#> $body[[1]]$declarations[[1]]
#> $body[[1]]$declarations[[1]]$type
#> [1] "VariableDeclarator"
#> 
#> $body[[1]]$declarations[[1]]$id
#> $body[[1]]$declarations[[1]]$id$type
#> [1] "Identifier"
#> 
#> $body[[1]]$declarations[[1]]$id$name
#> [1] "answer"
#> 
#> 
#> $body[[1]]$declarations[[1]]$init
#> $body[[1]]$declarations[[1]]$init$type
#> [1] "Literal"
#> 
#> $body[[1]]$declarations[[1]]$init$value
#> [1] 42
#> 
#> $body[[1]]$declarations[[1]]$init$raw
#> [1] "42"
#> 
#> 
#> 
#> 
#> $body[[1]]$kind
#> [1] "const"
#> 
#> 
#> 
#> $sourceType
#> [1] "script"
#> 
esprima_tokenize(js_code)
#> [[1]]
#> [[1]]$type
#> [1] "Keyword"
#> 
#> [[1]]$value
#> [1] "const"
#> 
#> 
#> [[2]]
#> [[2]]$type
#> [1] "Identifier"
#> 
#> [[2]]$value
#> [1] "answer"
#> 
#> 
#> [[3]]
#> [[3]]$type
#> [1] "Punctuator"
#> 
#> [[3]]$value
#> [1] "="
#> 
#> 
#> [[4]]
#> [[4]]$type
#> [1] "Numeric"
#> 
#> [[4]]$value
#> [1] "42"
#> 
#> 
#> [[5]]
#> [[5]]$type
#> [1] "Punctuator"
#> 
#> [[5]]$value
#> [1] ";"
#> 
#>