babel/lib/6to5/generation/whitespace.js

83 lines
1.9 KiB
JavaScript

module.exports = Whitespace;
var _ = require("lodash");
var util = require("../util");
// a helper to iterate array from arbitrary index
function getLookupIndex(i, base, max) {
i += base;
if (i >= max)
i -= max;
return i;
}
function Whitespace(tokens, comments) {
this.tokens = _.sortBy(tokens.concat(comments), "start");
this.used = [];
// speed up common case where methods are called for next tokens
this._lastFoundIndex = 0;
}
Whitespace.prototype.getNewlinesBefore = function (node) {
var startToken;
var endToken;
var tokens = this.tokens;
var token;
for (var j = 0; j < tokens.length; j++) {
var i = getLookupIndex(j, this._lastFoundIndex, this.tokens.length);
token = tokens[i];
// this is the token this node starts with
if (node.start === token.start) {
startToken = tokens[i - 1];
endToken = token;
this._lastFoundIndex = i;
break;
}
}
return this.getNewlinesBetween(startToken, endToken);
};
Whitespace.prototype.getNewlinesAfter = function (node) {
var startToken;
var endToken;
var tokens = this.tokens;
var token;
for (var j = 0; j < tokens.length; j++) {
var i = getLookupIndex(j, this._lastFoundIndex, this.tokens.length);
token = tokens[i];
// this is the token this node ends with
if (node.end === token.end) {
startToken = token;
endToken = tokens[i + 1];
this._lastFoundIndex = i;
break;
}
}
if (endToken.type.type === "eof") {
return 1;
} else {
var lines = this.getNewlinesBetween(startToken, endToken);
if (node.type === "Line" && !lines) {
// line comment
return 1;
} else {
return lines;
}
}
};
Whitespace.prototype.getNewlinesBetween = function (startToken, endToken) {
var start = startToken ? startToken.loc.end.line : 1;
var end = endToken.loc.start.line;
return util.mergeIntegerRange(this.used, start, end);
};