angular-docs-cn/aio/tools/transforms/angular-base-package/rendering/truncateCode.js

49 lines
1.4 KiB
JavaScript

module.exports = function() {
return {
name: 'truncateCode',
process: function(str, lines) {
if (lines === undefined) return str;
const parts = str && str.split && str.split(/\r?\n/);
if (parts && parts.length > lines) {
return balance(parts[0] + '...', ['{', '(', '['], ['}', ')', ']']);
} else {
return str;
}
}
};
};
/**
* Try to balance the brackets by adding closers on to the end of a string
* for every bracket that is left open.
* The chars at each index in the openers and closers should match (i.e openers = ['{', '('], closers = ['}', ')'])
*
* @param {string} str The string to balance
* @param {string[]} openers an array of chars that open a bracket
* @param {string[]} closers an array of chars that close a brack
* @returns the balanced string
*/
function balance(str, openers, closers) {
const stack = [];
// Add each open bracket to the stack, removing them when there is a matching closer
str.split('').forEach(function(char) {
const closerIndex = closers.indexOf(char);
if (closerIndex !== -1 && stack[stack.length-1] === closerIndex) {
stack.pop();
} else {
const openerIndex = openers.indexOf(char);
if (openerIndex !== -1) {
stack.push(openerIndex);
}
}
});
// Now the stack should contain all the unclosed brackets
while(stack.length) {
str += closers[stack.pop()];
}
return str;
}