.. | ||
.npmignore | ||
index.js | ||
LICENSE | ||
package.json | ||
README.md |
character-parser
Parse JavaScript one character at a time to look for snippets in Templates. This is not a validator, it's just designed to allow you to have sections of JavaScript delimited by brackets robustly.
Installation
npm install character-parser
Usage
Work out how much depth changes:
var state = parse('foo(arg1, arg2, {\n foo: [a, b\n');
assert(state.roundDepth === 1);
assert(state.curlyDepth === 1);
assert(state.squareDepth === 1);
parse(' c, d]\n })', state);
assert(state.squareDepth === 0);
assert(state.curlyDepth === 0);
assert(state.roundDepth === 0);
Bracketed Expressions
Find all the contents of a bracketed expression:
var section = parser.parseMax('foo="(", bar="}") bing bong');
assert(section.start === 0);
assert(section.end === 16);//exclusive end of string
assert(section.src = 'foo="(", bar="}"');
var section = parser.parseMax('{foo="(", bar="}"} bing bong', {start: 1});
assert(section.start === 1);
assert(section.end === 17);//exclusive end of string
assert(section.src = 'foo="(", bar="}"');
The bracketed expression parsing simply parses up to but excluding the first unmatched closed bracket ()
, }
, ]
). It is clever enough to ignore brackets in comments or strings.
Custom Delimited Expressions
Find code up to a custom delimiter:
var section = parser.parseUntil('foo.bar("%>").baz%> bing bong', '%>');
assert(section.start === 0);
assert(section.end === 17);//exclusive end of string
assert(section.src = 'foo.bar("%>").baz');
var section = parser.parseUntil('<%foo.bar("%>").baz%> bing bong', '%>', {start: 2});
assert(section.start === 2);
assert(section.end === 19);//exclusive end of string
assert(section.src = 'foo.bar("%>").baz');
Delimiters are ignored if they are inside strings or comments.
API
parse(str, state = defaultState(), options = {start: 0, end: src.length})
Parse a string starting at the index start, and return the state after parsing that string.
If you want to parse one string in multiple sections you should keep passing the resulting state to the next parse operation.
Returns a State
object.
parseMax(src, options = {start: 0})
Parses the source until the first unmatched close bracket (any of )
, }
, ]
). It returns an object with the structure:
{
start: 0,//index of first character of string
end: 13,//index of first character after the end of string
src: 'source string'
}
parseUntil(src, delimiter, options = {start: 0, includeLineComment: false})
Parses the source until the first occurence of delimiter
which is not in a string or a comment. If includeLineComment
is true
, it will still count if the delimiter occurs in a line comment, but not in a block comment. It returns an object with the structure:
{
start: 0,//index of first character of string
end: 13,//index of first character after the end of string
src: 'source string'
}
parseChar(character, state = defaultState())
Parses the single character and returns the state. See parse
for the structure of the returned state object. N.B. character must be a single character not a multi character string.
defaultState()
Get a default starting state.
isPunctuator(character)
Returns true
if character
represents punctuation in JavaScript.
isKeyword(name)
Returns true
if name
is a keyword in JavaScript.
State
A state is an object with the following structure
{
lineComment: false, //true if inside a line comment
blockComment: false, //true if inside a block comment
singleQuote: false, //true if inside a single quoted string
doubleQuote: false, //true if inside a double quoted string
regexp: false, //true if inside a regular expression
escaped: false, //true if in a string and the last character was an escape character
roundDepth: 0, //number of un-closed open `(` brackets
curlyDepth: 0, //number of un-closed open `{` brackets
squareDepth: 0 //number of un-closed open `[` brackets
}
It also has the following useful methods:
.isString()
returnstrue
if the current location is inside a string..isComment()
returnstrue
if the current location is inside a comment.isNesting()
returnstrue
if the current location is anything but at the top level, i.e. with no nesting.
License
MIT