Grunt insert string after pattern in file - node.js

Question

I'm building a custom task for grunt that finds a particular font, and basically outputs a definition that uses a PHP variable for configuring that particular font.
It uses underscore and postcss.
It groups all CSS selectors that use that font, and outputs a string similar to this one:
selector1, selector2, selector3 {
font-family: <?php echo $font_1 ?>, Font 2, Font 3, Font 4;
}
Here is the code for the custom task:
// Extract configurable font data
// ======================================================================
grunt.registerTask('extractfontdata', 'Extract configurable properties', function () {
console.log('Extracting configurable font data');
var match = /Myriad Pro/gim;
var contents = grunt.file.read('assets/css/leadscon.css');
var css = postcss(function (css) {
var findings = {};
css.eachDecl(function (decl) {
if (decl.value.match( match ) && decl.parent.selector !== undefined) {
var fonts = decl.value.replace(/(\r\n|\n|\r|"|')/gm, "").split(',');
var prop = _.find(fonts, function(font) { return font.match(match) });
var finding = findings[ prop ] = findings[ prop ] || {};
finding.selectors = finding.selectors || [];
finding.fontstack = finding.fontstack || [];
finding.selectors.push( decl.parent.selector.replace(/(\r\n|\n|\r|"|'|\s)/gm, "").split(',') );
finding.fontstack.push( fonts );
finding.selectors = _(finding.selectors).chain().flatten().uniq().value();
finding.fontstack = _(finding.fontstack).chain().flatten().uniq().value();
}
});
var result = '';
var j = 0;
for ( var font in findings ) {
findings[font].fontstack.every(function(f, i) {
if (f.match(font)) {
findings[font].fontstack[i] = '<?php echo $font_' + j++ + ' ?>';
}
});
result += findings[font].selectors.join(',') + ' { font-family: ' + findings[font].fontstack.join(',') + ' } ';
}
console.log(result);
// Now insert result into header.php
}).process(contents);
});
This currently, will set result to:
body,.footer-widget.widget_nav_menu.widget-title
{
font-family: <?php echo $font_0 ?>, PT Sans, Helvetica Neue, Helvetica, Arial, sans-serif
}
h1,h2,h3,h4,h5,h6,.h1,.h2,.h3,.h4,.h5,.h6,.widget.widget-title,.widget_lc_cta,.header-widget.widget_lc_events.events,.widget_accordion_widget.accordion-widget.resp-tabs-container>.resp-accordion,article.single>.article-header.breadcrumbs,article.single>.article-header.meta
{
font-family: <?php echo $font_1 ?>, Open Sans Condensed, PT Sans, Helvetica Neue, Helvetica, Arial, sans-serif
}
I've added this code to header.php:
<style>
/* extractfontdata */
</style>
Now, how do I find the string "extractfontdata" in header.php, and insert result after it?

Answer 1

Well in case anyone is wondering, this worked for me:
// Now insert result into header.php
var header = grunt.file.read('header.php').split('\n');
var line_1 = _.indexOf(header, _(header).find(function(el) { return el.match(/extractfontdata/i) }) );
var line_2 = _.indexOf(header, _(header).find(function(el) { return el.match(/endextractfontdata/i) }));
var start = Math.min(line_1, line_2) + 1;
var end = Math.max(line_1, line_2);
var num = Math.min((end - start), 0);
header.splice(start, num, result);
for ( var i = start-2; i <= end+2; i++) {
console.log(header[i]);
}
grunt.file.write('header.php', header.join('\n'));