253 lines
4.7 KiB
JavaScript
253 lines
4.7 KiB
JavaScript
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/*!
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* Stylus - Node
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* Copyright (c) Automattic <developer.wordpress.com>
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* MIT Licensed
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*/
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/**
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* Module dependencies.
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*/
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var Evaluator = require('../visitor/evaluator')
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, utils = require('../utils')
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, nodes = require('./');
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/**
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* Initialize a new `CoercionError` with the given `msg`.
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*
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* @param {String} msg
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* @api private
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*/
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function CoercionError(msg) {
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this.name = 'CoercionError'
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this.message = msg
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if (Error.captureStackTrace) {
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Error.captureStackTrace(this, CoercionError);
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}
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}
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/**
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* Inherit from `Error.prototype`.
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*/
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CoercionError.prototype.__proto__ = Error.prototype;
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/**
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* Node constructor.
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*
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* @api public
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*/
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var Node = module.exports = function Node(){
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this.lineno = nodes.lineno || 1;
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this.column = nodes.column || 1;
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this.filename = nodes.filename;
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};
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Node.prototype = {
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constructor: Node,
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/**
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* Return this node.
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*
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* @return {Node}
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* @api public
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*/
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get first() {
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return this;
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},
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/**
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* Return hash.
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*
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* @return {String}
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* @api public
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*/
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get hash() {
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return this.val;
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},
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/**
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* Return node name.
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*
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* @return {String}
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* @api public
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*/
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get nodeName() {
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return this.constructor.name.toLowerCase();
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},
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/**
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* Return this node.
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*
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* @return {Node}
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* @api public
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*/
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clone: function(){
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return this;
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},
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/**
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* Return a JSON representation of this node.
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*
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* @return {Object}
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* @api public
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*/
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toJSON: function(){
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return {
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lineno: this.lineno,
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column: this.column,
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filename: this.filename
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};
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},
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/**
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* Nodes by default evaluate to themselves.
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*
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* @return {Node}
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* @api public
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*/
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eval: function(){
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return new Evaluator(this).evaluate();
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},
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/**
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* Return true.
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*
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* @return {Boolean}
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* @api public
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*/
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toBoolean: function(){
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return nodes.true;
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},
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/**
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* Return the expression, or wrap this node in an expression.
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*
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* @return {Expression}
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* @api public
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*/
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toExpression: function(){
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if ('expression' == this.nodeName) return this;
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var expr = new nodes.Expression;
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expr.push(this);
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return expr;
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},
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/**
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* Return false if `op` is generally not coerced.
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*
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* @param {String} op
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* @return {Boolean}
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* @api private
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*/
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shouldCoerce: function(op){
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switch (op) {
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case 'is a':
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case 'in':
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case '||':
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case '&&':
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return false;
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default:
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return true;
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}
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},
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/**
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* Operate on `right` with the given `op`.
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*
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* @param {String} op
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* @param {Node} right
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* @return {Node}
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* @api public
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*/
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operate: function(op, right){
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switch (op) {
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case 'is a':
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if ('string' == right.first.nodeName) {
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return nodes.Boolean(this.nodeName == right.val);
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} else {
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throw new Error('"is a" expects a string, got ' + right.toString());
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}
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case '==':
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return nodes.Boolean(this.hash == right.hash);
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case '!=':
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return nodes.Boolean(this.hash != right.hash);
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case '>=':
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return nodes.Boolean(this.hash >= right.hash);
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case '<=':
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return nodes.Boolean(this.hash <= right.hash);
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case '>':
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return nodes.Boolean(this.hash > right.hash);
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case '<':
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return nodes.Boolean(this.hash < right.hash);
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case '||':
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return this.toBoolean().isTrue
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? this
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: right;
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case 'in':
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var vals = utils.unwrap(right).nodes
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, len = vals && vals.length
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, hash = this.hash;
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if (!vals) throw new Error('"in" given invalid right-hand operand, expecting an expression');
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// 'prop' in obj
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if (1 == len && 'object' == vals[0].nodeName) {
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return nodes.Boolean(vals[0].has(this.hash));
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}
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for (var i = 0; i < len; ++i) {
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if (hash == vals[i].hash) {
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return nodes.true;
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}
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}
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return nodes.false;
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case '&&':
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var a = this.toBoolean()
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, b = right.toBoolean();
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return a.isTrue && b.isTrue
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? right
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: a.isFalse
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? this
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: right;
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default:
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if ('[]' == op) {
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var msg = 'cannot perform '
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+ this
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+ '[' + right + ']';
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} else {
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var msg = 'cannot perform'
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+ ' ' + this
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+ ' ' + op
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+ ' ' + right;
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}
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throw new Error(msg);
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}
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},
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/**
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* Default coercion throws.
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*
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* @param {Node} other
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* @return {Node}
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* @api public
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*/
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coerce: function(other){
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if (other.nodeName == this.nodeName) return other;
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throw new CoercionError('cannot coerce ' + other + ' to ' + this.nodeName);
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}
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};
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