Respect useTabs option when indenting an opening JSX element

[jsnajdr]

Steps to reproduce:
Run this node script:

const recast = require('.');

// parse some code into AST
let ast = recast.parse([
	"function x(a, b) {",
	"\treturn (",
	"\t\t<div>",
	"\t\t\t{ b }",
	"\t\t</div>",
	"\t);",
	"}"
].join("\n"));

// change the variable identifier in JSX to trigger reprint
ast.program.body[0].body.body[0].argument.children[1].expression.name = 'a';

// print the output with useTabs=true
let output = recast.print(ast, { useTabs: true }).code;

// replace tabs with '~' and spaces with '_'
output = output.replace(/ /g, "_").replace(/\t/g, "~");

// print the output code with visible whitespace
console.log(output);

Expected result:
The output is indented with tabs:

function_x(a,_b)_{
~return_(
~~<div>
~~~{_a_}
~~</div>
~);
}

Actual result:
There are spaces before the JSX opening element:

function_x(a,_b)_{
~return_(
~____<div>
~~~{_a_}
~~</div>
~);
}

The cause of the bug is:

• in return statement, a JSX element argument gets some extra indentation
• the Lines.prototype.join method uses spaces to create the indent and doesn't respect the useTabs option

The fix is to use a smarter algorithm from the Lines.prototype.sliceString function.

However, this requires passing a new parameter to the join method and recursively add options to many many calls. I'm wondering if there is a better solution for this. Do all the calls to concat and Lines.prototype.join need the options argument?

[benjamn]

Can you stick to four spaces per tab when adding new implementation code, please? I realize you're a fan of tabs (nothing wrong with that), but consistency is important here.

[Hexcede]

Can you stick to four spaces per tab when adding new implementation code, please? I realize you're a fan of tabs (nothing wrong with that), but consistency is important here.

I apologize in advance, but I really can't help emphasizing the enormous amount of irony in the statement "consistency is important here" in reference to indents in a PR that is targeting a design flaw that produces inconsistent indents. (Not trying to be snippy or anything, I'm sorry if it came across that way)

Could issue #315 as well as this PR possibly be addressed sometime soon since this project appears like it's still maintained? These issues have been around for almost six years now, it would be pretty nice. In the meantime I switched to babel's generator which seems to have everything I need.

[jsnajdr]

Can you stick to four spaces per tab when adding new implementation code, please? I realize you're a fan of tabs (nothing wrong with that), but consistency is important here.

Oh, sorry for submitting broken commits like this :( I pushed a tabs-to-spaces change, and also changed the indentString function to avoid param destructuring -- the tests were failing on older versions of Node.js that don't have good enough ES6 support.