R語言中使用JavaScript的詳細(xì)講解

#js_typeof(),如果代碼無效將引發(fā)SyntaxError,用于驗(yàn)證單個(gè)函數(shù)或?qū)ο?callback<-'function test(x, y){var z = x*y ;return z;}'
js_typeof(callback) #'function'
js_typeof('function(x,y){return x + y}') #'function'
conf<-'{foo : function(){},bar : 123}'
js_typeof(conf) #'object'

#JavaScript程序驗(yàn)證:由JavaScript語句集合組成,用js_validate_script()函數(shù)
jscode<-readLines(system.file("js/uglify.min.js",package="js"),warn=FALSE)
js_validate_script(jscode) #TRUE
js_validate_script('function(x, y){return x + y}', error = FALSE) #FALSE不允許在全局范圍內(nèi)定義匿名函數(shù)

esprima_tokenize(text,range=FALSE,loc=FALSE,comment=FALSE) #返回data.frame
text:JavaScript代碼的字符向量,range:以0為基準(zhǔn)注釋每個(gè)標(biāo)簽的起始位置+結(jié)束位1:300,loc:注釋每個(gè)標(biāo)簽起始行+起始列+終止行+終止列的位置,numeric類型

esprima_parse(text,jsx = FALSE,range = FALSE,loc = FALSE,tolerant = FALSE,tokens = FALSE,comment = FALSE) #返回'JS_EVAL'類型,解析成樹形結(jié)構(gòu)

cat(coffee_compile("square = (x) -> x * x"))
cat(coffee_compile("square = (x) -> x * x",bare=T))

demo<-readLines(system.file("example/demo.coffee", package = "js"))
cat(demo, sep = "\n")
js<-coffee_compile(demo) #

code <- "function test(x, y){x = x || 1; y = y || 1; return x*y;}"
cat(uglify_reformat(code, beautify = TRUE, indent_level = 2))

code <- "var foo = 123"
jshint(code)