Question

maven有一个功能我在package.json中错过了很多。在maven .pom文件中，您可以在父项目中定义变量，并在子项目的pom文件中使用它们。

npm有这样的东西吗？我们正在构建模块化项目，我想集中定义依赖版本，并在各自的package.json文件中使用它们。

由于

Answer 1

可以引用任何键，从$npm_package_开始，并为您所下的每个级别添加下划线。

示例：

{ "name": "appname", "version": "0.0.1"}

名称可以通过以下方式访问：$npm_package_name

Answer 2

您可以在package.json

中拥有config对象

以下是两个带示例的链接：

http://www.marcusoft.net/2015/08/npm-scripting-configs-and-arguments.html#npm-configuration

http://ianmcnally.me/blog/2016/2/4/variables-in-npm-scripts

Answer 3

在Windows上，您应该使用%variable_name%。例如：

{
   "name": "app_name",
   "version": "1.0.0",
   "custom": {
      "key": "any value"
   }
}

您可以使用%npm_package_name%，%npm_package_version%和%npm_package_custom_key%来获取它。

Answer 4

我将 package.json 文件作为变量导入到我的节点项目中以获取对象结构，而不是使用 $npm_package_name。这会将其从 JSON 转换为 JS 对象

let package = require("./package.json");

Answer 5

我花了一段时间才发现我的错误：

我在 powershell 上运行，你必须使用 <!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8"> <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no"> <meta name="description" content=""> <meta name="author" content=""> <title>Communities Fighting Covid</title>  <link href="vendor/bootstrap/css/bootstrap.min.css" rel="stylesheet">  <link href="css/modern-business.css" rel="stylesheet"> <script src="https://cdnjs.cloudflare.com/ajax/libs/d3/6.2.0/d3.min.js"></script> </head> <body> <script> var margin = {top: 20, right: 160, bottom: 35, left: 30}; var width = 960 - margin.left - margin.right, height = 500 - margin.top - margin.bottom; var svg = d3.select("body") .append("svg") .attr("width", width + margin.left + margin.right) .attr("height", height + margin.top + margin.bottom) .append("g") .attr("transform", "translate(" + margin.left + "," + margin.top + ")"); /* Data in strings like it would be if imported from a csv */ var data = [ { race: "A", positive: "60", total: "600"}, { race: "C", positive: "58", total: "500"}, { race: "D", positive: "85", total: "600"}, { race: "E", positive: "56", total: "500"}, { race: "F", positive: "89", total: "700"}, { race: "G", positive: "62", total: "400"} ]; // Transpose the data into layers var keys= ["positive", "total"]; var dataset = d3.stack().keys(keys)(data); // Set x, y and colors var x = d3.scaleBand() .domain(data.map(function(d) { return d.race; })) .range([10, width-10], 0.02); var y = d3.scaleLinear() .domain([0, d3.max(dataset, function(d) { return d3.max(d, function(d) { return d[0] + d[1]; }); })]) .range([height, 0]); var colors = ["b33040", "#d25c4d"]; // Define and draw axes var yAxis = d3.axisLeft() .scale(y) .ticks(5) .tickSize(-width, 0, 0) .tickFormat( function(d) { return d } ); var xAxis = d3.axisBottom() .scale(x) .tickFormat(data.race); // change this to get x values to reflect new svg.append("g") .attr("class", "y axis") .call(yAxis); svg.append("g") .attr("class", "x axis") .attr("transform", "translate(0," + height + ")") .call(xAxis); // Create groups for each series, rects for each segment var groups = svg.selectAll("g.cost") .data(dataset) .enter().append("g") .attr("class", "cost") .style("fill", function(d, i) { return colors[i]; }) var rect = groups.selectAll("rect") .data(function(d) { return d; }) .enter() .append("rect") .attr("x", function(d) { return x(d.data.race); }) .attr("y", function(d) { return y(d[0] + d[1]); }) .attr("height", function(d) { return y(d[0]) - y(d[0] + d[1]); }) .attr("width", x.bandwidth()) .on("mouseover", function() { tooltip.style("display", null); }) .on("mouseout", function() { tooltip.style("display", "none"); }) .on("mousemove", function(d) { var xPosition = d3.pointer(this)[0] - 15; var yPosition = d3.pointer(this)[1] - 25; tooltip.attr("transform", "translate(" + xPosition + "," + yPosition + ")"); tooltip.select("text").text(d.y); }); // Draw legend var legend = svg.selectAll(".legend") .data(colors) .enter().append("g") .attr("class", "legend") .attr("transform", function(d, i) { return "translate(30," + i * 19 + ")"; }); legend.append("rect") .attr("x", width - 18) .attr("width", 18) .attr("height", 18) .style("fill", function(d, i) {return colors.slice().reverse()[i];}); legend.append("text") .attr("x", width + 5) .attr("y", 9) .attr("dy", ".35em") .style("text-anchor", "start") .text(function(d, i) { switch (i) { case 0: return "Total Cases"; case 1: return "Positive Cases"; } }); // Prep the tooltip bits, initial display is hidden var tooltip = svg.append("g") .attr("class", "tooltip") .style("display", "none"); tooltip.append("rect") .attr("width", 30) .attr("height", 20) .attr("fill", "white") .style("opacity", 0.5); tooltip.append("text") .attr("x", 15) .attr("dy", "1.2em") .style("text-anchor", "middle") .attr("font-size", "12px") .attr("font-weight", "bold"); </script> </body> 或 $env:npm_package_name 在那里访问变量。

我怎样才能在package.json中使用变量？

5 个答案: