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Mini Shell
Mini Shell
/**
* @fileoverview Translates tokens between Acorn format and Esprima format.
* @author Nicholas C. Zakas
*/
/* eslint no-underscore-dangle: 0 */
//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------
// none!
//------------------------------------------------------------------------------
// Private
//------------------------------------------------------------------------------
// Esprima Token Types
const Token = {
Boolean: "Boolean",
EOF: "<end>",
Identifier: "Identifier",
PrivateIdentifier: "PrivateIdentifier",
Keyword: "Keyword",
Null: "Null",
Numeric: "Numeric",
Punctuator: "Punctuator",
String: "String",
RegularExpression: "RegularExpression",
Template: "Template",
JSXIdentifier: "JSXIdentifier",
JSXText: "JSXText"
};
/**
* Converts part of a template into an Esprima token.
* @param {AcornToken[]} tokens The Acorn tokens representing the template.
* @param {string} code The source code.
* @returns {EsprimaToken} The Esprima equivalent of the template token.
* @private
*/
function convertTemplatePart(tokens, code) {
const firstToken = tokens[0],
lastTemplateToken = tokens[tokens.length - 1];
const token = {
type: Token.Template,
value: code.slice(firstToken.start, lastTemplateToken.end)
};
if (firstToken.loc) {
token.loc = {
start: firstToken.loc.start,
end: lastTemplateToken.loc.end
};
}
if (firstToken.range) {
token.start = firstToken.range[0];
token.end = lastTemplateToken.range[1];
token.range = [token.start, token.end];
}
return token;
}
/**
* Contains logic to translate Acorn tokens into Esprima tokens.
* @param {Object} acornTokTypes The Acorn token types.
* @param {string} code The source code Acorn is parsing. This is necessary
* to correct the "value" property of some tokens.
* @constructor
*/
function TokenTranslator(acornTokTypes, code) {
// token types
this._acornTokTypes = acornTokTypes;
// token buffer for templates
this._tokens = [];
// track the last curly brace
this._curlyBrace = null;
// the source code
this._code = code;
}
TokenTranslator.prototype = {
constructor: TokenTranslator,
/**
* Translates a single Esprima token to a single Acorn token. This may be
* inaccurate due to how templates are handled differently in Esprima and
* Acorn, but should be accurate for all other tokens.
* @param {AcornToken} token The Acorn token to translate.
* @param {Object} extra Espree extra object.
* @returns {EsprimaToken} The Esprima version of the token.
*/
translate(token, extra) {
const type = token.type,
tt = this._acornTokTypes;
if (type === tt.name) {
token.type = Token.Identifier;
// TODO: See if this is an Acorn bug
if (token.value === "static") {
token.type = Token.Keyword;
}
if (extra.ecmaVersion > 5 && (token.value === "yield" || token.value === "let")) {
token.type = Token.Keyword;
}
} else if (type === tt.privateId) {
token.type = Token.PrivateIdentifier;
} else if (type === tt.semi || type === tt.comma ||
type === tt.parenL || type === tt.parenR ||
type === tt.braceL || type === tt.braceR ||
type === tt.dot || type === tt.bracketL ||
type === tt.colon || type === tt.question ||
type === tt.bracketR || type === tt.ellipsis ||
type === tt.arrow || type === tt.jsxTagStart ||
type === tt.incDec || type === tt.starstar ||
type === tt.jsxTagEnd || type === tt.prefix ||
type === tt.questionDot ||
(type.binop && !type.keyword) ||
type.isAssign) {
token.type = Token.Punctuator;
token.value = this._code.slice(token.start, token.end);
} else if (type === tt.jsxName) {
token.type = Token.JSXIdentifier;
} else if (type.label === "jsxText" || type === tt.jsxAttrValueToken) {
token.type = Token.JSXText;
} else if (type.keyword) {
if (type.keyword === "true" || type.keyword === "false") {
token.type = Token.Boolean;
} else if (type.keyword === "null") {
token.type = Token.Null;
} else {
token.type = Token.Keyword;
}
} else if (type === tt.num) {
token.type = Token.Numeric;
token.value = this._code.slice(token.start, token.end);
} else if (type === tt.string) {
if (extra.jsxAttrValueToken) {
extra.jsxAttrValueToken = false;
token.type = Token.JSXText;
} else {
token.type = Token.String;
}
token.value = this._code.slice(token.start, token.end);
} else if (type === tt.regexp) {
token.type = Token.RegularExpression;
const value = token.value;
token.regex = {
flags: value.flags,
pattern: value.pattern
};
token.value = `/${value.pattern}/${value.flags}`;
}
return token;
},
/**
* Function to call during Acorn's onToken handler.
* @param {AcornToken} token The Acorn token.
* @param {Object} extra The Espree extra object.
* @returns {void}
*/
onToken(token, extra) {
const that = this,
tt = this._acornTokTypes,
tokens = extra.tokens,
templateTokens = this._tokens;
/**
* Flushes the buffered template tokens and resets the template
* tracking.
* @returns {void}
* @private
*/
function translateTemplateTokens() {
tokens.push(convertTemplatePart(that._tokens, that._code));
that._tokens = [];
}
if (token.type === tt.eof) {
// might be one last curlyBrace
if (this._curlyBrace) {
tokens.push(this.translate(this._curlyBrace, extra));
}
return;
}
if (token.type === tt.backQuote) {
// if there's already a curly, it's not part of the template
if (this._curlyBrace) {
tokens.push(this.translate(this._curlyBrace, extra));
this._curlyBrace = null;
}
templateTokens.push(token);
// it's the end
if (templateTokens.length > 1) {
translateTemplateTokens();
}
return;
}
if (token.type === tt.dollarBraceL) {
templateTokens.push(token);
translateTemplateTokens();
return;
}
if (token.type === tt.braceR) {
// if there's already a curly, it's not part of the template
if (this._curlyBrace) {
tokens.push(this.translate(this._curlyBrace, extra));
}
// store new curly for later
this._curlyBrace = token;
return;
}
if (token.type === tt.template || token.type === tt.invalidTemplate) {
if (this._curlyBrace) {
templateTokens.push(this._curlyBrace);
this._curlyBrace = null;
}
templateTokens.push(token);
return;
}
if (this._curlyBrace) {
tokens.push(this.translate(this._curlyBrace, extra));
this._curlyBrace = null;
}
tokens.push(this.translate(token, extra));
}
};
//------------------------------------------------------------------------------
// Public
//------------------------------------------------------------------------------
export default TokenTranslator;
Zerion Mini Shell 1.0